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Wed Dec 07, 2011 12:04 pm

I have tried everything and my lights will still not work!! The only lights that work are my back running lights, but not other ones work, i have tried replacing the bulbs and everything that i can think of, the 3,4,5,6,7,8 fuses aren't working which means they aren't getting power... Any suggestions?

Wed Dec 07, 2011 12:35 pm

Which one of your Bugs?
What lights don't work?
Headlights?
Brake lights?
Turn signal lights?
Speedometer lights?
All but your running taillights?

Wed Dec 07, 2011 1:12 pm

Something is wrong with the bus fuse bar.
Probably burnt through at one time
You need power on both sides through the fuse!
Or, you are gong to have to replace or buy single fuse cases and rewire each one so that it has power !

Jerry

Wed Dec 07, 2011 1:45 pm

It is in a 72' super beetle, and the only lights that work are the rear running lights, so the turn signals don't work, the brake lights don't work or anything

Wed Dec 07, 2011 2:16 pm

The front park lights should be working if the rear lights and license plate are...they're powered off the same fuse.

The headlight switch which provides power to the rear lights gets its power from the ignition switch, which gets its power from three fuses that are hot all the time...start there, you should have three fuses that are hot all the time - the bus would appear to be intact here as power is still flowing from the battery through 30 wire, to the fusebox, across the bus, and onward to the ignition switch.

The brakelights should have power off of Terminal 15 of the ignition switch, as does the ignition coil, horn, gas gauge, gen/oil/turn power, emergency switch power, and brake warning lamp power.

Wed Dec 07, 2011 3:12 pm

get a dmm
then its easy.

Wed Dec 07, 2011 3:22 pm

DMM don't put any current in the system, better yet a simple old test light.

Wed Dec 07, 2011 4:02 pm

Here is the wiring diagram for a 72 I can vouch for it as I used it when I restored my bug and pulled all the wires off without marking them :oops:

Wed Dec 07, 2011 5:42 pm

Wpeeper wrote: the 3,4,5,6,7,8 fuses aren't working which means they aren't getting power... Any suggestions?
First off, are you reading the fuse numbers correctly? Fuse#1 should be closest to left side of car. Just making sure we are working to the same standard.

Did anything happen that caused this massive electrical failure?

Fuses 3-6 are for the headlights. They only receive power while the headlight switch is ON. You didn't mention fuses 9-12. Are they powered?

Start with fuses 7-9 as they are powered directly from the battery. (If someone replaced your fuse box with a later one then only 8-9 are powered by the battery). Look at the back of the fuse box and confirm the heavy gauge red wire from the VR connects to the common bus that powers all thee fuses. Parking lights are powered by the same battery source, but do not depend on these fuses.

Fuse 10 is powered by the "X" circuit of the ignition switch. This should have 12v+ while the ignition is ON. The headlights are powered by the same source. If you don't have power here when the ignition switch is ON your headlights won't work. Headlights are powered from the non-protected side of this fuse.

Lastly, fuses 11-12 are powered by the ignition switch. The same source that powers the ignition coil. So if your engine is running these fuses should also be powered. Brakes and turn signals ares powered from here, as well as the speedo lights.

Wed Dec 07, 2011 5:44 pm

Chris Vellat wrote: DMM don't put any current in the system, better yet a simple old test light.
Actually, when the meter is set for resistance (ohms) it DOES inject a small current to measure continuity.
A test lamp is a completely passive tool... unless you area using a continuity tester which also injects a small current like an ohm meter.

Wed Dec 07, 2011 5:48 pm

i would check your fuse box to see if its messed up in any way. Did it all happen suddenly or is this a problem that has always existed and your just gettting to it? could be the whole wiring harness

Wed Dec 07, 2011 8:38 pm

ashman40 wrote: Chris Vellat wrote: DMM don't put any current in the system, better yet a simple old test light.
Actually, when the meter is set for resistance (ohms) it DOES inject a small current to measure continuity.
A test lamp is a completely passive tool... unless you area using a continuity tester which also injects a small current like an ohm meter.

A lamp puts much more current on the wiring than a DMM (or any of my Fluke or Milwaukee units)...when a DMM will show voltage, it's entirely possible a test light will not illuminate because of high resistance in the circuit...If a DMM says you have voltage, sure, you might have the potential for some (so you then test for continuity if a problem still exists), with a test light, if it's on, you're good - you can even observe high resistance as the light glows dim or bright.

A DMM can be misleading, that's all I'm saying...they're still valuable tools...but one cannot be fooled by a test light.

Wed Dec 07, 2011 8:53 pm

ashman40 wrote: ...Fuse 10 is powered by the "X" circuit of the ignition switch. This should have 12v+ while the ignition is ON. The headlights are powered by the same source. If you don't have power here when the ignition switch is ON your headlights won't work. Headlights are powered from the non-protected side of this fuse.

Lastly, fuses 11-12 are powered by the ignition switch. The same source that powers the ignition coil. So if your engine is running these fuses should also be powered. Brakes and turn signals ares powered from here, as well as the speedo lights.

Headlights also must receive power from Terminal 30 in order to work, this should be hot all the time at the switch, `72 actually fuses this wire from fuse 8. Where earlier cars, the power went directly to the headlight switch - in order to get the highest possible voltage at the headlights - the path of least resistance.

It should read 'the bottom three speedo indicator lights', the illumination lights are powered off the headlight switch...the rear window defrost indicator light is powered off of fuse 10, and the high beam indicator is powered from the load size of fuse 5

Wed Dec 07, 2011 9:17 pm

Chris Vellat wrote: Headlights also must receive power from Terminal 30 in order to work, this should be hot all the time at the switch, `72 actually fuses this wire from fuse 8.
The #30 connection on the headlight switch only powers the parking lights. For those model years that have the "X" circuit from the ignition switch, the high and low beams are powered by the "X" terminal on the headlight switch. This allows the headlight power to be diverted while the engine is cranking, giving max power to the starter.

Also, if you look at the wiring diagram you will see that the #30 wire that goes to the headlight switch gets its power from the "unprotected" input side of the fuse box. So even if you pull all the fuses, the #30 terminal at the headlight switch should still have power.

Chris Vellat wrote: It should read 'the bottom three speedo indicator lights', the illumination lights are powered off the headlight switch...the rear window defrost indicator light is powered off of fuse 10, and the high beam indicator is powered from the load size of fuse 5
Good catch! :)

Wed Dec 07, 2011 10:22 pm

ashman40 wrote: Chris Vellat wrote: Headlights also must receive power from Terminal 30 in order to work, this should be hot all the time at the switch, `72 actually fuses this wire from fuse 8.
The #30 connection on the headlight switch only powers the parking lights. For those model years that have the "X" circuit from the ignition switch, the high and low beams are powered by the "X" terminal on the headlight switch. This allows the headlight power to be diverted while the engine is cranking, giving max power to the starter.

Also, if you look at the wiring diagram you will see that the #30 wire that goes to the headlight switch gets its power from the "unprotected" input side of the fuse box. So even if you pull all the fuses, the #30 terminal at the headlight switch should still have power

I guess I didn't remember that as well as I thought...I've been working on the electrical in the back of the car lately :oops:

Whoops, got my switches crossed...I was looking at the emergency switch.

You wouldn't happen to have a source for an autostick ATF lamp holder, insulated double terminal?

Thu Dec 08, 2011 8:19 am

Chris Vellat wrote: A lamp puts much more current on the wiring than a DMM (or any of my Fluke or Milwaukee units)...
Since a test lamp is not powered I'm guessing you actually mean it has a greater "load" (resistance) instead of current? Or, maybe you mean because the test lamp has more resistance than a MM it leaves more current in the circuit?

Chris Vellat wrote: when a DMM will show voltage, it's entirely possible a test light will not illuminate because of high resistance in the circuit...If a DMM says you have voltage, sure, you might have the potential for some (so you then test for continuity if a problem still exists), with a test light, if it's on, you're good - you can even observe high resistance as the light glows dim or bright.

A DMM can be misleading, that's all I'm saying...they're still valuable tools...but one cannot be fooled by a test light.
While I agree with some of what you have said here I usually find people get misled by their test lamp, especially when testing their ignition coil.
I heard more than a few people think they have a bad coil because their test lamp lights up bright when the ignition switch its ON and they test the #15 (+) terminal. But when they go to test the #1 (-) side the test lamp does NOT light up at all. Their first thought is the coil internal wiring is bad.

If they had realized that because their points were CLOSED all current from the coil (-) was flowing down the green wire to ground. No (or very little) current was flowing through the test lamp because current will take the path of least resistance (the points offer ZERO resistance) to ground. If they had rotated their crank until the points OPENED, the only path to ground would be through the test lamp and they would know that power was flowing through the coil.

I wonder how many coils over the years have been replaced by owners that thought their coils were bad just because their test lamps didn't light up?

You are correct, both are valuable tools, but don't let your test lamp fool you ;)

Thu Dec 08, 2011 1:34 pm

ashman40 wrote: Chris Vellat wrote: A lamp puts much more current on the wiring than a DMM (or any of my Fluke or Milwaukee units)...
Since a test lamp is not powered I'm guessing you actually mean it has a greater "load" (resistance) instead of current? Or, maybe you mean because the test lamp has more resistance than a MM it leaves more current in the circuit?
Current on the circuit wiring...as measured by an ammeter/DMM

ashman40 wrote: Chris Vellat wrote: when a DMM will show voltage, it's entirely possible a test light will not illuminate because of high resistance in the circuit...If a DMM says you have voltage, sure, you might have the potential for some (so you then test for continuity if a problem still exists), with a test light, if it's on, you're good - you can even observe high resistance as the light glows dim or bright.

A DMM can be misleading, that's all I'm saying...they're still valuable tools...but one cannot be fooled by a test light.
While I agree with some of what you have said here I usually find people get misled by their test lamp, especially when testing their ignition coil.
I heard more than a few people think they have a bad coil because their test lamp lights up bright when the ignition switch its ON and they test the #15 (+) terminal. But when they go to test the #1 (-) side the test lamp does NOT light up at all. Their first thought is the coil internal wiring is bad.

If they had realized that because their points were CLOSED all current from the coil (-) was flowing down the green wire to ground. No (or very little) current was flowing through the test lamp because current will take the path of least resistance (the points offer ZERO resistance) to ground. If they had rotated their crank until the points OPENED, the only path to ground would be through the test lamp and they would know that power was flowing through the coil.

I wonder how many coils over the years have been replaced by owners that thought their coils were bad just because their test lamps didn't light up?

You are correct, both are valuable tools, but don't let your test lamp fool you ;)

Perhaps setting the timing statically by timing light is a lost skill. The benefit is they probably discovered the error of their ways quickly, when the new coil did the same thing ;)

Fri Apr 27, 2012 7:23 am

Turned out to be the light switch, who woulda thought aha

Fri Apr 27, 2012 1:57 pm

Stranger things have happened. I thought I had an electrical issue on my '73 at one time because all of a sudden my low beams quit working, high beams were fine. Fuse was fine, traced the wiring, it was fine, turned out that both low beam filiments let go at the exact same time.

Sat Apr 28, 2012 8:52 am

The problem as stated could not have been resolved by replacing only the switch, if everything was factory, did you find anything odd behind the dash?