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Longmont1302
Samba Member
Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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 Posted: Thu Jan 11, 2018 7:42 pm Post subject: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Neither my tail lights nor my license plate light come on when I pull my light switch out all the way on my 71 Super Beetle. My brake lights and rear turn indicators work fine.
I should mention that the PO installed a new fuse box, and I'm not 100% sure he wired it exactly as he should have. I don't know that he didn't either, but I have my doubts.
That said, I've tried a few different new fuses in the far left slot of the fuse box, and have briefly tried replacing each of the other 8 amp fuses in the box with no success. Can someone suggest my next step?
Scott |
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Speedbird73
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Joined: May 04, 2017
Posts: 36
Location: Copake NY
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| Posted: Thu Jan 11, 2018 7:52 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Well, first step would be to check the fuse box wiring vs. that of your owner's manual. It's likely that the PO did not wire it correctly. Are you popping fuses?
Second step would be to go back the the tail lights, ensure that everything is correctly plugged in with eachother, and make sure to check the ground. Should be a little tab located right inside of the wheel well in the engine compartment. Additionally, make sure that your bulbs are installed correctly. A backwards bulb will cause it to ground out, and you will go through hell trying to get your rear running lights to work and your brake lights to work.
As for the license plate lamp, that should ground through the passenger's side tail light, so it is likely connected incorrectly.
Finally, if it is a newer switch, you may have to jiggle the switch a little bit in order for the lights to come on, and stay on.
Do you have headlights and front running lights?
You can find wiring diagrams here in the archives section if you do not have an owner's manual.
Hope this helps! |
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Longmont1302
Samba Member
Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Sat Jan 20, 2018 4:51 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| Speedbird73 wrote: |
| Well, first step would be to check the fuse box wiring vs. that of your owner's manual. It's likely that the PO did not wire it correctly. |
Thanks, Speedbird. That first step took me a while. I found 3 different fuse box configurations for a 1971 113; one in a 71 owners manual PDF, a second in a 71 instruction manual PDF, and a third in the orange Bentley. The instruction manual appears to be what the PO used for a general plan. Oddly enough, the wiring diagram in the Bentley seems close (even though it’s fuse box was way different). Here’s what I believe the first few slots of the fuse box do (I've confirmed 3-6 by pulling the fuses, and am guessing on the rest):
1. R tail light, R & L parking light, license light
2. L tail light
3. Low beam L (chart says R)
4. Low beam R (chart says L)
5. High beam L (chart says R)
6. High beam R (chart says L)
The headlights, brake lights, turn signals, and emergency flashers all work well. The tail lights, parking lights, and license light do not work. I don’t pop any fuses. I’ve tested and/or replaced all the fuses.
When I clamp the test light up to ground, and put the pointer to the fuse box, neither side of any of the fuses above lights up the tester. If I hook the tester to the + battery terminal, then point it in the fuse box. both sides of all the above fuses light it up. (The higher number fuses, not listed here, seem to be reversed from this and light up when the tester is connected to ground.)
When I clamp the tester to a screw in the engine department, then point the tester to the light socket for a rear turn signal or brake light, the tester will light up (when I turn on the flashers or step on the brake). With the lights on, I cannot get the tester to light up when pointed to either connection on the center rear light bulbs (which should be the tail lights) or when I point it to the license light. Removing the bulbs during the test doesn’t help. Jiggling the light switch doesn’t have any impact. I think this means I have power at the fuse box but not at the lights, but I'm not sure what to do next.
I’d welcome any suggestions for next steps or for resources on learning how to troubleshoot this part of the electrical system; there’s not much in the Muir book on this. |
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Cusser
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Joined: October 02, 2006
Posts: 31360
Location: Hot Arizona
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sb001
Samba Member
Joined: May 19, 2011
Posts: 10406
Location: NW Arkansas
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| Posted: Sat Jan 20, 2018 7:59 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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A picture of your fuse box wiring would be extremely beneficial here. However, going by what you posted above regarding the layout of your 1-2 fuses, that does correspond to what the technical wiring diagram shows.
So the most obvious conclusion is that you are simply not getting power from your headlight switch to those 1 and 2 fuses which power the parking and taillights.
There should be a solid gray wire, from terminal 58 on your headlight switch, that runs straight to the unfused side of fuse #2. This is power for those fuses for your parking and taillights (and license plate light.) Make sure this wire is coming into the UNFUSED side of fuse #2, this will be the side of the fuse box with a metal strap bridging over to fuse #1 so that incoming power is split between the two fuses.
Something else that I'm curious about- in your last post you say:
"With the lights on, I cannot get the tester to light up when pointed to either connection on the center rear light bulbs (which should be the tail lights)"
This sound like you are saying your brake lights are on another bulb.. is this true? Your taillights and brake lights share the same center mounted bulbs. Those are dual-filament bulbs, with one filament operating the brake lights, and one filament operating the taillights. Just want to be sure you DO have dual-filament bulbs in the center sockets, and properly connected to the brake and taillight wiring.
_________________
I'm the humblest guy on this board.
1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor |
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Longmont1302
Samba Member
Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Sat Jan 20, 2018 10:46 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Thanks for the replies.
| Cusser wrote: |
| Tell us if the front parking lights come on, they are on the same circuit. |
They do not.
Here's the fuse box wiring:
It's tough to see in the photo, so here's my drawing of Slots 1 and 2:
There is a solid gray wire that runs to one side of #2 (I'm not sure which side is unfused.)
| sb001 wrote: |
| Just want to be sure you DO have dual-filament bulbs in the center sockets, and properly connected to the brake and taillight wiring. |
Yes. the center bulb is the dual filament kind. The pins on the base of the bulb are in different places (they're right across from each other on the single filament bulbs). Only these bulbs will fit here. Attached to the back of this socket is one black and one gray wire. |
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sb001
Samba Member
Joined: May 19, 2011
Posts: 10406
Location: NW Arkansas
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| Posted: Sat Jan 20, 2018 11:18 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| Longmont1302 wrote: |
Thanks for the replies.
| Cusser wrote: |
| Tell us if the front parking lights come on, they are on the same circuit. |
They do not.
Here's the fuse box wiring:
It's tough to see in the photo, so here's my drawing of Slots 1 and 2:
There is a solid gray wire that runs to one side of #2 (I'm not sure which side is unfused.)
| sb001 wrote: |
| Just want to be sure you DO have dual-filament bulbs in the center sockets, and properly connected to the brake and taillight wiring. |
Yes. the center bulb is the dual filament kind. The pins on the base of the bulb are in different places (they're right across from each other on the single filament bulbs). Only these bulbs will fit here. Attached to the back of this socket is one black and one gray wire. |
Thanks for the pics. OK, so the solid gray wire running into fuse #2 is correct, it is going into the unfused side of the fuse box as it should be. See those metal bridging straps between fuses on that side of the fuse panel? That tells us that is the unfused side of the fuse box- the side where incoming power is routed. The purpose of those metal straps is to distribute incoming power between certain fuses.
Now, there should be a strap between your #2 and #1 fuses, to distribute parking/ taillight power coming in on that solid gray wire between both those fuses. But in your case your fuse box does not have this bridging strap for some reason between your #2 and #1 fuses. So someone has compensated by running that blue wire between the two fuses instead, to carry power from #2 fuse over to #1 fuse. This solution will work just fine, AS LONG AS your #2 fuse is good! This is because that wire has been run off the OUTPUT side of #2 fuse over to the INPUT side of #1 fuse.
So DOUBLE CHECK that #2 fuse- if it's no good you will NOT be getting power to any of those lights you mentioned- even if your #1 fuse is good!- because that wire depends on power getting through #2 fuse first.
If that fuse is good, then let's concentrate on making sure that solid gray wire is actually carrying power to those fuses. This wire should be coming from 58 terminal on your headlight switch. When you pull the switch on (even if it's just to the parking light setting) that should transfer power through that wire to #2 fuse. So let's test that wire for 12v power. Turn your headlight switch on (you should not have to turn the key on for this test, as the parking/ taillights should run straight off battery power.) Then unplug that wire from the #2 fuse, then take your test light and connect the + test lead to the bare end of that wire, and ground the - test lead. When you touch the - lead to ground that test bulb should light up. If it does not, then you are not getting 12 volts off the headlight switch through that wire, and it's a good bet the other end of that gray wire is not properly connected to terminal 58 on your headlight switch, or it's possible your switch is malfunctioning (not likely since you have headlights, but it's possible.)
_________________
I'm the humblest guy on this board.
1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor |
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Longmont1302
Samba Member
Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Sun Jan 21, 2018 3:53 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Hi sb001,
Thanks for the help. I double-checked fuses #1 and 2. They are both good.
| sb001 wrote: |
| When you pull the switch on (even if it's just to the parking light setting) that should transfer power through that wire to #2 fuse. |
For whatever reason, I need to have the key on for the lights to work. I turned the key on, pulled the light switch out two clicks to the ON position, clipped the tester to ground, and poked the gray wire on the #2 fuse – nothing.
Next, I removed the light switch from the dash:
Since it's hard to see in the photo, here's my diagram:
Tab #58 does have the gray wire on it. With the key on, and the switch in the "out twice" on position, I put the tester probe to the base of the 58 tab. Nothing. I then put the probe to every tab on the switch. Only the fatter red/black wire and the white/black lit up the tester.
What's next? Do I pull the wires off the switch, bring it inside the warm house (it's snowing today) and test it separately? -Scott |
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sb001
Samba Member
Joined: May 19, 2011
Posts: 10406
Location: NW Arkansas
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| Posted: Sun Jan 21, 2018 5:12 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Hey Scott,
i think everything is wired correctly at your headlight switch. I believe the problem may be at your fuse panel. Going back and looking at your fuse box photo again, I notice something that may explain the issue you're having.
Take a look at this picture of your fuse panel with my added descriptions:
The descriptors I added are to help you understand the CONSTANT power flow coming from your battery into the fuse box. That thick red/white striped wire should be incoming battery power, it brings constant battery power into the unfused side of your #9 fuse. Then you see that metal bridge strap between your #9 and #8 fuse? This carries that constant power over to the #8 fuse to that thick solid red wire, which then carries constant power to your ignition switch. Note that ALL of this stays on the UNFUSED side of your fuse panel- none of this power actually goes through a fuse.
Now, there SHOULD be another bridge strap connecting your #8 fuse over to your #7 fuse, thereby sending the same unfused constant battery power over to that smaller solid red wire coming off the unfused side of #7 fuse. This smaller red wire should go to tab #30 on your headlight switch. THIS IS THE WIRE THAT CARRIES THE POWER TO YOUR HEADLIGHT SWITCH FOR THE PARKING LIGHTS AND TAILLIGHTS. When you pull your headlight switch on to that first position, the power coming in through this red wire to #30 terminal on your headlight switch should transfer through the switch, and out that solid gray wire from #58 terminal, to the #1 and #2 fuses we have discussed earlier.
However you are MISSING the bridging strap between your #8 and #7 fuses. See where I circled that burned looking wire in red in the photo above? I think that might be where our problem lies. Because you have no bridging strap there, it looks like someone connected a wire there to transfer power over from #8 fuse to #7 fuse- but that wire looks to be pretty much toast. You MUST get power from #8 over to #7 fuse to then send power up through that thinner red wire to your headlight switch for your parking and taillights.
We can do a simple test here to see if that is indeed the problem. Pull your headlight switch on to the FIRST setting. Then go around to your fuse box and disconnect that thick red/ white stripe wire from fuse #9 (the one marked "Incoming power from battery" in the photo above.) Touch it to that solid red wire marked "Power out to headlight switch" where it comes off #7 fuse. See if your parking lights and taillights suddenly light up. If so, then we've found the problelm.
_________________
I'm the humblest guy on this board.
1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor |
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Cusser
Samba Member
Joined: October 02, 2006
Posts: 31360
Location: Hot Arizona
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| Posted: Sun Jan 21, 2018 7:10 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| Longmont1302 wrote: |
| For whatever reason, I need to have the key on for the lights to work. |
1971 and newer need key in "run" position for the headlights to work.
You stating "lights" only leads to vague interpretations.
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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Longmont1302
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Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Sun Jan 21, 2018 9:47 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| sb001 wrote: |
| Pull your headlight switch on to the FIRST setting. Then go around to your fuse box and disconnect that thick red/ white stripe wire from fuse #9 (the one marked "Incoming power from battery" in the photo above.) Touch it to that solid red wire marked "Power out to headlight switch" where it comes off #7 fuse. See if your parking lights and taillights suddenly light up. If so, then we've found the problelm. |
I took the rotten jumper wire between 7 and 8, pulled the light switch out one click, then took the wire off of 9 and placed it on 7. Doing so caused all the missing lights (front parking lights, tail lights, license plate light) to come on.
Thanks for that. I don't know what's more impressive, your troubleshooting skills or your eyesight (to recognize the bad wire in the photo).
Do I simply replace that jumper wire, or should I be concerned as to what caused it to deteriorate? |
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Longmont1302
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Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Sun Jan 21, 2018 9:51 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| Cusser wrote: |
| Longmont1302 wrote: |
| For whatever reason, I need to have the key on for the lights to work. |
1971 and newer need key in "run" position for the headlights to work.
You stating "lights" only leads to vague interpretations. |
Hi Cusser,
Good point, thanks. I try to be clear, but I missed the mark on this one.
Scott |
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sb001
Samba Member
Joined: May 19, 2011
Posts: 10406
Location: NW Arkansas
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| Posted: Mon Jan 22, 2018 4:54 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| Longmont1302 wrote: |
I took the rotten jumper wire between 7 and 8, pulled the light switch out one click, then took the wire off of 9 and placed it on 7. Doing so caused all the missing lights (front parking lights, tail lights, license plate light) to come on.
Thanks for that. I don't know what's more impressive, your troubleshooting skills or your eyesight (to recognize the bad wire in the photo).
Do I simply replace that jumper wire, or should I be concerned as to what caused it to deteriorate? |
Good to hear!
Yes a nice thick short jumper wire between those two fuses (7 & 8 ) should do the trick without compromising anything. OR, if you have a spare spade terminal coming off the unfused side of either 9 or 8 fuse, you could just swap that red wire from #7 fuse over to one of those.
_________________
I'm the humblest guy on this board.
1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor |
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Longmont1302
Samba Member
Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Mon Jan 22, 2018 10:10 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Thanks again for your help!
-Scott |
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ashman40
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Joined: February 16, 2007
Posts: 15982
Location: North Florida, USA
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| Posted: Tue Jan 23, 2018 12:34 am Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Glad you got it working. Just a comment on the blue wire on fuses #1 and #2...
From the pic it looks like fuse #1 is connected to the OUTPUT side of fuse #2. This would mean the 8A fuse in #2 position is carrying the load of all the bulbs powered by both fuse #1 and #2. If you remove the #2 fuse I’m guessing ALL the parking lights go out.
The problem is the PO replaced the earlier ‘71 fuse box with a ‘73-later one. In the earlier fuse box the #1 and #2 fuses were bridged on the INPUT side with a brass bar. On the later years fuse #1 and #2 were separate and the grey wire from the headlight switch had two female terminals on the end of the wire. One for fuse #1 and the other for fuse #2. You need to create a short jumper between the INPUT side of fuse #1 and #2. To do this you will probably need a splitter to create two male terminals on of the the INPUTS to allow the jumper wire to connect to that fuse.
The same goes for fuse #7. In pre-73 model years you could find the INPUT side of #7, #8 and #9 fuses bridged together. But in later years #7 (spare fuse) was left as a stand alone. This is a good thing as it allows your or the dealer to choose whether fuse #7 was powered from the battery or the ignition.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road  }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Longmont1302
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Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Thu Jan 25, 2018 10:13 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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Thanks, Ashman40.
Inspired by my Samba-fueled success with the tail lights, and armed with a wiring diagram, I decided to add lights to the speedometer (which has never had any as long as I've had the car). I had purchased the missing sockets and bulbs a while ago, but finally wired them up to terminal 58b on the switch tonight, and nothing... ... until I realized there's a dimmer built into the switch. I turned it up and they worked fine.
Man, I am ready for some night time driving now. I feel like a responsible adult. Thanks again to sb001.
I have two non-crucial questions:
1. The wiring diagram lists in mm how thick each wire should be. What's the risk of the too small or two big wire?
2. From what I've found, a 1971 Super Beetle should have a 90 MPH speedometer, so this one's probably not original, right? Oh well, it looks pretty good. |
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ashman40
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Joined: February 16, 2007
Posts: 15982
Location: North Florida, USA
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| Posted: Fri Jan 26, 2018 12:55 am Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| Longmont1302 wrote: |
| 1. The wiring diagram lists in mm how thick each wire should be. What's the risk of the too small or two big wire? |
The the mm rating you are describing is not the thickness (diameter) but rather the costs-sectional surface area in square-mm (mm^2). The larger the cross-sectional area the more current the wire can safely carry and the more heat it can dissipate. The devices the wires power have a specific power rating which needs a certain number of amps to run properly. The wires in the circuit need to safely carry this current load.
The fuses in the fuse box are designed to protect the wiring. You design the electrical circuits so the fuse will blow when the current load exceeds the capacity of the wires in the circuit. This prevents the wires from overheating and melting. If you change the wire size to a smaller one (smaller cross sectional area) you risk the wires overheating before the fuse can blow. Best case, your wire insulation melts. Worse case, the insulation catches fire and in turn your car catches fire.
Changing the wires to a larger wire size is fine. The wires will be able to carry more current than the circuit is designed to carry. The only down side is the wire will cost more and you will not get any benefit from it if the correct size wires will do the job just fine.
On the other hand, if you add 100W off-road headlights which are almost twice the wattage of the OE 55W headlights you would NEED to replace the headlight wires with heavier gauge wires to carry the extra load from the upgraded headlights.
Additional note, American Wire Gauge (AWG) ratings work in reverse. The smaller the gauge number the larger is its capacity to carry current. When you get down below 1gauge the size becomes 0, 00 and 000 gauge. Most acvw wires are in the 8 to 16gauge range. You can find the conversion chart here.
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AshMan40
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'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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Longmont1302
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Joined: October 01, 2015
Posts: 324
Location: Longmont, CO
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| Posted: Fri Jan 26, 2018 4:32 pm Post subject: Re: Tail Light Troubleshooting Tips: 71 Super Beetle |
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| ashman40 wrote: |
| The the mm rating you are describing is not the thickness (diameter) but rather the costs-sectional surface area in square-mm (mm^2). |
Thanks for that distinction and for the chart. I was looking at a different chart that was converting diameter in mm to wire gauge, and that was leading me astray.
Thanks too, for the explanation of why using larger wire may be acceptable while using smaller wire than suggested should be avoided as it may not properly dissipate heat. |
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