Turn Signal Fault

[johnny 999]

Hi

I wonder if anybody can help. One of my front signals has stopped working. Bulb is fine as it works on the other indicator. Test meter shows power at circa 6v intermittently as it flashes but the light doesn't operate - even with outside of holder using a cable so not the holder itself. I thought power was too low but its exactly the same at the other side which does work and light up the bulb.

When operating it is fast as if bulb has blown. When hazards operates its normal speed but bulb still doesn't work.

Could it be relay or flasher unit - but if so why is there still power to the bulb holder?

Thanks for any advice

[Q-Dog]

Could be a poor ground or a failure in the lamp socket.
_________________
Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[ashman40]

It would help if you identified your model (STD or SB) and model year?? Also if you were more detailed and explained which SIDE front turn signal is not working?? It would help by letting me describe which colored wires you should be looking for.

Test for voltage at these spots and report back the voltage readings you get...

[In the below descriptions I have allowed for some voltage loss due to old wires but ideally there should be little to no voltage loss if the wiring were new]
Find the constant 12v powered fuse on the fuse box (has 12v even with ignition OFF). Test for voltage. You should get a reading of around 12.5v here at the fuse box (battery should read 12.6v).

Turn the ignition ON. Find the ignition powered fuses. Test for voltage at these fuses. You should read 12.4v.

Find the flasher relay. One of the wires powering the relay will have 12v while the ignition switch is ON and the E-Flasher switch if OFF. Test this terminal for voltage. It should be the same as the fuse box.

With the ignition ON, move the turn signal lever to the working side. One of the other terminals on the flasher relay will now have a pulsing 12v. Test this terminal for voltage. It should read a pulsing 12v.

Depending which side is not working, find the black/green (right) or black/white (left) wire coming from the turn signal switch. Follow it to a junction. Test this junction for pulsing voltage while the turn signal lever is in the turn position for this side. Test both sides and compare the voltage readings. They should be the SAME as the only difference is that turn signal switch is directing the current to either one wire or the other.

Just inside the fender find the junction where the parking light and turn signal light wiring junctions with the pigtails that run to the light assemblies. Test the voltage at the left or right turn signal wire.

As you progress further and further from the battery the voltage will drop slightly. If you see a significant voltage drop (more than 0.1v) you have found a bad connection. Try disconnecting wires at the junction and cleaning with wire brush or sandpaper. This will reduce the resistance and improve current flow and you should get better voltage readings.

Report back your voltage readings and where you find large voltage drops.
_________________
AshMan40
---------------------------
'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!}

[johnny 999]

Thanks Ashman

Its a 73 1300 standard car. All of the wiring is new so that shouldn't be an issue. Albeit it was installed by me so that maybe . And its the front passenger side of a right hand drive car. the indicator housings are not great quality (Chinese copies I think) and rely on contact with the body for earth. As I have fibreglass wings I ran separate cable instead

I'll go through the test routine you suggest and come back if anything is not as it should be

Cheers

[ashman40]

Are you running the '73 stock-style front turn signal assemblies or some earlier style lights? Prior to '67/'68, the parking lights were in the headlight assemblies and the turn signal assemblies on the fenders were single filament bulbs ONLY. It is NOT possible (not without significant re-wiring) to use these single-filament assemblies for BOTH turn and parking lights. Others have tried this and failed. I want to make sure this is not your situation.

If your problem is with only the front right light assembly, disconnect all the wires at the junction in the trunk and test each wire individually.
Turn the parking lights ON and test the grey wire for voltage.
Turn the right turn signal ON and test for pulsing voltage on the black/green wire.
If the voltage is low for the turn signals, bypass the flasher relay and see if this makes a difference. Remove the white wire from the #49 (+) terminal of the relay. Remove the wire(s) from the #49a terminal of the relay. Connect these wires together and make sure they don't touch anything metal. Now when you use the turn signal lever the lights should turn ON solid and not flash. You should get a 12v reading at the end of the wire for the front right light assembly. If you are still only getting a 6v reading you have too much resistance in the wiring.
Set your multimeter to read resistance and test the resistance between the front end of the black/green wire and the end at the 4-wire junction near the dash. It is a single length of wire so the resistance should be much less than 1ohm. It may even show as 0-ohms. If you see more than 1ohm you have a bad wire.

On the question of ground, from '70-onward the front turn signal assemblies (and headlights) came with a dedicated ground wire which was attached to a ground point inside the trunk. So it wouldn't matter if the fender (wing) were metal or fiberglass. Earlier model years DID ground thru the fender. In such cases you would need to add a ground wire between the light assembly and a point on the (metal) body.
_________________
AshMan40
---------------------------
'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!}

[RichNJohn]

Resurrecting this post for a slightly different problem on my 72 Super (Vert). The other day the turn signal switch started smoking and stopped working. I knew the unit was pretty worn and had a new German replacement switch ready so I pulled the steering wheel and replaced the switch. Initially everything seemed to be working fine except I must have gotten the cancelling post on the horn ring thingie in the wrong orientation because the signals won't self cancel now.

So down the road I go when smoke starts coming out of the steering column again. Hope I didn't completely cook the new switch before pulling the plug to stop the burning. I looked at the relay on the fuse panel and it was all melted on one side. So I guess maybe the relay went south and that's what is cooking my switch? Is there somewhere else I should be looking? I hate to put a new relay and potentially another new switch only to have something down stream of the relay cause all the new stuff to cook too.

Any suggestions are welcome, thanks.

By the way, what is the proper orientation for the horn ring cam that cancels the turn signal switch? Should it be at 3:00 next to the cancelling cam on the switch?

[johnny 999]

At long last got some time on the car to test as instructed.

12v @ battery and perm fuse on board. 12v on fuse to indicators.

indicators themselves working indicator only 8v ish and non working 6v (so probably the issue).

At the relay I'm getting 12v to the working indicator so losing 4 in transit. But only 7 or so to the non working. Thought maybe the relay was the issue so replaced that - same outputs.

So I'm guessing I need to replace the cables from the relay to the lights because of the drop? incidentally both seem to out put from the 3 pin relay with merged blue and black/white wires.

Does it also indicate there is a fault on the turn switch on the steering wheel as 12 v from the signal fuse but only 7v making it to the relay output?

thanks VM

[johnny 999]

At long last got some time on the car to test as instructed.

12v @ battery and perm fuse on board. 12v on fuse to indicators.

indicators themselves working indicator only 8v ish and non working 6v (so probably the issue).

At the relay I'm getting 12v to the working indicator so losing 4 in transit. But only 7 or so to the non working. Thought maybe the relay was the issue so replaced that - same outputs.

So I'm guessing I need to replace the cables from the relay to the lights because of the drop? incidentally both seem to out put from the 3 pin relay with merged blue and black/white wires.

Does it also indicate there is a fault on the turn switch on the steering wheel as 12 v from the signal fuse but only 7v making it to the relay output?

thanks VM

[sb001]

[ashman40]

[RichNJohn]

Thanks for the reply regarding the proper alignment of the cancelling ring