A Different Turn Signal Problem

[Paulporsche]

My turn signals had been working intermittently but had been fine lately. Then the emergency flashers stopped working so I bought a new Wehrle relay from our host. Then this started:

The emergency flashers now work fine but the passenger front light is dim. When the right turn is indicated the light is dim and it flashes too quickly (of course). Looking at the bulb I could see that the upper filament, which is the dimmer one, worked. The lower, brighter one is the one that is supposed to be working, but doesn't.

I swapped in a new bulb with the same results. I cleaned all contacts and reinstalled the bulb with the same results. I also swapped the bulbs, swapped the sockets and swapped the leads. Each time I had the same result.

I turned on the headlights with the ignition off. This turned on the turn signals as well. They were both equally bright, with the lower filament on. The rear flashers work correctly in all modes.

I have yet to reinstall the old relay.

The only time the problem arises is when the new relay is engaged, and it only started as soon as the new relay was installed, so I'm thinking it must be the relay.

Anyone have any other thoughts?

Thanks.

[fintstone]

Does the emergency flasher work now?

[Paulporsche]

Yes, but the passenger front light is on the dim filament.

The rear signal lights work correctly in all modes.

The new relay seems to be "telling" the wrong filament to light up.

[porschenut]

Funny, I just spent a couple of hours fixing a RF turn signal issue. The problem was the spring behind the socket had sprung itself free so the bulb wasn't being held firmly enough to make continuous contact.

Anyway, I'm almost certain that the relay only controls the flashing filaments, not the dimmer filament for the running/parking lights. So my first suggestion is that the wiring inside the housing (behind the bulb) is swapped so that the wrong filament (dim one) is being activated by the turn signal circuit. Have you removed the chromed metal piece and looked behind it to check the wire connections? You might compare the RF wiring to the LF wiring, as they should be identical.

Wait, never mind. You said the signals were working fine lately so the wiring must be ok unless you've been messing with it. I think you should put the old relay back in and see if anything is different.

[Paulporsche]

I thought the same thing at first, porschenut, so I swapped everything around--the wires, the socket, the bulbs...all with the same result.

I'm going to replace the old relay and let you know what happens.

[Paulporsche]

Reinstalled the old relay with the previous results--the turn signals again work at the correct same speed and illumination side to side at the front. Rears still fine. Emergency flashers still not working. No other change was made for this test.

The new relay MUST be the culprit. It is somehow activating the incorrect filament in turn signal mode.

[Paulporsche]

Well, this really has me stumped.

I've replaced the new Wuhrle relay with another new one, with the same results--the right side signal only illuminates the lesser filament, causing a lower brightness and an increased flashing frequency. I've changed the bulbs front and rear, cleaned the contacts, reversed contacts and housings, and still get the same result. The rears illuminate correctly and the emergency flashers are fine.

When I replace the newest relay with the old Uro brand one that does not cause the hazard lights to flash, the signals all work correctly.

It seems that somehow the newest 2 relays are causing the wrong filament to illuminate.

I'm going to see if I get different voltage readings off the 2 sides of the relay.

I've also just remembered an old thread of mine, in which I had a turn signal fault that I cured by renewing the ground connection to the headlights. Think I'll look into that.

In the meantime, anyone have any other ideas?

Thanks.

[Paulporsche]

For some reason the front signal lights that were on the car were Sylvania 1157, which are not correct, being of a higher wattage than spec. So I installed the ones our host recommends, number 7528.

Note: our host shows 7528 for both front and rear signals. They do not fit in the rears on my car. 1156 work. It has just 1 connector and 1 filament.

Now I have an added problem: When I activate the passenger side signal, the headlight on that side flashes on and off with the signal! The headlight is very weak, just barely illuminated, but it is flashing on and off. Somehow the headlight seems to be controlled by the relay. Both are flashing weakly and at a higher rate than normal. Left side is fine.

When the headlights are on and the signal is off, the headlights work fine.

Could the column switch be causing the problem?

[Paulporsche]

Found the problem--a bad ground to the turn signal light.

I temporarily connected a wire to the ground side of the socket and the hood latch and now the light illuminates brightly, in its correct frequency, and the small light in the H4 does not flash.

Now I just have to connect a new ground wire permanently.

RESOLVED. Ran a new ground wire from the signal housing up to the headlight bucket, which solved the problem.

Why the Uro relay worked flashing the signals fine and the Wuhrle one didn't I still don't know.

[porschenut]

Uro relays are notoriously unreliable. There was a thread a year or two back on Rennlist about them. Plus, sometimes the relay is not the correct type, even though the catalog says it's correct. I avoid all Uro-branded products unless I have no other reasonable alternative. Glad to hear you got it fixed. As usual, the diagnosis is far more difficult than the fix.

[porsche964guy]

Paul,
"Why the Uro relay worked flashing the signals fine and the Wuhrle one didn't I still don't know."

So your saying the URO relay worked and the Wuhrle did not?

[Paulporsche]

Dave,

I would definitely second that! I thought that by redoing the ground connections, that would be sufficient. Turns out, I must have been cleaning and reconnecting a compromised wire.

Porsche964guy,

Yes, at first. The Uro was able to flash the signals correctly, with the right illumination and frequency, while with the Wuhrle, the illumination was weak and the flashing too fast. The Uro however, was unable to get the emergency flashers going at all, and sometimes wasn't able to get anything going. This is why I got the new Wuhrle and went through the whole diagnosis. Obviously, I wanted the correct frequency and brightness, and all systems functioning.

Just to be clear, I used the Wuhrle for the diagnostic testing, and am continuing to use it. Everything is now operating correctly. The Uro will be relegated to spare status.

A nice little bonus: with the new ground wire it looks to me that all my lights, including headlights, are brighter. Probably no surprise there, but it was nice to see.

[tirwin]

Glad you got it sorted out. Bad grounds can cause all sorts of crazy problems. After chasing down some wiring issues I noticed how much brighter some lights were too. The seat beat/e brake light in particular used to be faintly lit. Now it is very brightly illuminated.

[Paulporsche]

Tim,

It's probably one of those things to file away for future use. When the lights seem dim or erratic, start with the grounds!

[porsche964guy]

I was having trouble with my rear turn signals a little while ago. Eventual found bare wires shorting and pulling out of the light socket. Reattached them, taped them up and everything was fine. Our cars are not new anymore and need a little TLC.