Hello,
My 940 drivers side turn signal doesn't work unless the headlights are off. Also, the left rear turn signal glows dimly. I assumed that it was from the lense falling off and water getting into the socket but it's been replaced, and the socket cleaned up. Could it be the relay? Also, the emergency flashers work no matter what, headlights on or not. And, I checked the grounds behind the headlights. Where are the rear taillight grounds? Thanks!

You have a ground problem in the left front fender area.

If you look in the FAQ you will see that the grounds in the left front fender can get so bad that the car will stall when you put on the high beams and they rob everything of grounds.

Find a terminal strip welded to the fender, and look for other grounds.

If an item does not have a ground wire (as the lights do as their body is plastic) then the item gets its ground by its mounting.

As I remember, there is a ground on the anti-lock tower, and some items might need better contact with the body , such as heat paste on the ignition resistor or whatever Volvo calls it.

Also, make sure that the body - to - engine ground straps are in good condition - I think that there is one on top of the engine, and one on the bottom.

Thanks for the response! My first thought when this problem started was a bad ground. I looked around behind the drivers headlight and everthing appeared tight. I will check all grounds. Not sure where the taillights are grounded but, I will follow the wires. Thanks!

Ok, I am getting frustrated. I only have left turn signal if headlights are off. The right turn signal works with headlights on or off. the emergency flashers always work. The left rear turn signal glows dimly with headlights or running lights on. I have checked, cleaned, and slightly mashed the spade connectors slightly for the grounds behind the headlights. And, the ground points are tight. I have also checked all engine to chassis grounds, and found them tight.

I have spent the day looking at the FAQ's, and wiring diagrams on the interweb looking for the ground point for the rear tailights. All of the diagrams I have looked at show the international symbol for a ground, but it just shows it going to ground, not where it is actually grounded. Can anyone tell me where the taillights ground to the chassis? I followed the tail light wiring and it looks to me like the grounding wires go back up to the front of the car. Thanks! Have mercy on my soul, I really have searched TB and googled the p-ss out of this!

Hi,

I only have 1994 and 1995 green book wiring scheme if this could be of help to you. In sedan - the tail lights ground is under the plastic cover around the boot lock where both sides share the same ground. In wagon - its next to the tail lights themselves, one separately for each side. In all cases the black wire goes to ground.

Regards,
Amarin.

Amarin,
Thanks. Found it. That ground is clean and tight. I also checked the fuse and it is fine too. The front light grounds are all tight . Not sure what to try next.

Next to check is the turn signal switch itself at the steering. There could be burnt contacts inside this switch (for left turn signalling) due to previous water damage to the left rear lamp socket.

The emergency flasher switch bypasses the turn signal switch by connecting ALL turn signal lights together. The emergency switch is rarely used thus still have good contacts.

Only thing I can't figure out completely is how this involves the headlights. Headlights have different circuit than the turn lights. The only thing headlights and turn lights have in common is that they share the same stalk with same physical switch but different set of contacts inside.

Anyways the turn signal switch is suspect.

Regards,
Amarin.

Amarin,
OK, I pulled the turn signal stalk/switch out and it appears it is un-serviceable. Two little plastic clips do nothing to help split it apart because of the rivets that hold the whole thing together. And, I am sure its one of those things that fly apart if you could open it with springs and stuff inside. I guess I am looking for a used one to swap it out with, and hope that's the problem. I am too chicken to drill the rivets out as parts would surely be everywhere. Thanks!

Try spraying some cleaner into it. Work it around and dry it out. Hopefully that clears something inside. Install it back. See if at least you could get the signal working without the headlight interfering. If that works then it really was the switch. But you can't use that switch for long as all the lubricating grease inside had been washed off by cleaner. Time to get another switch.

Regards,
Amarin.

Holy crap! I am so screwed now.... I went to the pullnpray and got a headlight switch and a turn signal assy. and replaced them both one at a time and no change in my problem.

I had a radio installed years ago for "free" and the village idiot that put it in was a hack. Somehow, he used a hot headlight wire SOMEWHERE to power the radio. I hated it because the headlights always had to be on for the radio to work. I am not so sure he didn't ground something somewhere....

This could complicate things. Try disconnecting the radio to see if that makes things right. Most radio have electrical connector for disconnection.

Regards,
Amarin.

Amarin,
OK, I found a special little alpine fuse box that came with the radio. I will disconnect it and see what happens. Just to re-cap, I have swapped out:

turn signal, red bulb fail, headlight switch, and, I just tried the turn signal flasher relay (NOT the emergency one) and no change. I am thinking it's not the hatchet radio install that's my problem (I hope not) I am going to pull the headlight fuses and see what happens also.

Thanks for your help, no one else wants to touch this, it one of those problems that could have multiple causes.

Ok, I'm feeling real stupid but it kind of isn't my fault!. The stinkin yellow double filament bulb is somehow internally shorted ! A brand new bulb! I tried everything else but the stupid bulb. I put an old bulb in and it works fine. Who knew? Thanks to those that replied!

I started by pulling headlight and left and right running/turn signal fuses one by one until the left turn signal worked with headlights on. That narrowed my search. Now I remember that it started when I put two new double filament bulbs in. However, it didn't register for some damn reason, because they were brand new right out of the Chinese package! Thanks for sticking with me Amarin!

I had another thought on this, it could possibly be the light switch. I have spares of the 240 light switch, and I am going to cross reference and see if they are compatible.

Earlier 240 light switch has either 3 terminals or 5 terminals. For 240 years 1986 to 1993 has 6 terminals like 940 switch but has different part number.

Regards,
Amarin.

Amarin,
I am back to work this week and won't get to check the turn signal contacts for a couple of days. I was wondering if that could be the problem. I don't get how the headlights are involved either. But, when I turn on headlights, the turn arrow on the dash glows dimly, like the left rear turn signal and, turn headlights off, and both turn signals work correctly. I am also going to swap the flasher for a known good one. I will report back when I have checked the turn signal at the steering wheel. And, as wgusler on TB recommended, taking a wire straight from the battery - to the tail light grounding point. Thanks again!