Turn Signal Dimly Flashing In Cluster - Ground Issue?

[sefeing]

Recently replaced my voltage regulator (it was VERY very shot) on my '88 944 S. Now the car sits just below 14V, versus just above 12V

Since that, a little electrical gremlin has popped up that I can't figure out.

My turn signal indicator in my gauge cluster flashes ever so slightly to the pulses of the engine. If it turn the signal on, it flashes bright and then totally off, but when there's no indicator on, it pulses to the engine - video below

What ground should I start with? I cleaned all grounds on the back of the cluster, as well as the two grounds next to each other under the dash - there's one more I can't seem to reach.

Link to video:

[Evan]

Check the main engine ground strap and the grounds on the inner left fender. Since it pulses with the engine, a bad engine ground is the most likely cause.

[Tom]

That's a new one for me, so just brainstorming here... I'd be inclined to check the actual blinker lights at night to see if they are also lighting up faintly. Either way, but especially if they are, I'd be inclined to look at the relay to see if it's not staying open when the blinkers are off. Does the light still flicker if you remove the relay? If so, that might point toward something in the cluster or grounds. Also, any chance you have LED blinker bulbs? They can cause issues with old-school flasher relays that rely on more current flow to work properly.

[sefeing]

That's a new one for me, so just brainstorming here... I'd be inclined to check the actual blinker lights at night to see if they are also lighting up faintly. Either way, but especially if they are, I'd be inclined to look at the relay to see if it's not staying open when the blinkers are off. Does the light still flicker if you remove the relay? If so, that might point toward something in the cluster or grounds. Also, any chance you have LED blinker bulbs? They can cause issues with old-school flasher relays that rely on more current flow to work properly.

mmm, great question! ill have to run jt tongiht and see if i can see any flickering - will take a look at the relay too.

i do have LED’s in the cluster! i was wondering if that could potentially be the issue for that reason exactly. maybe ill order a handful of the stock size incandescents and see if that helps.

will see if i can get a scope in to check the ground on the bell housing and take a look a the fender grounds too. going to end up pulling my intake soon to be able to rebuild the TB with your kit tom, so a good time to clean those bell housing grounds, they’re a headache to get to on the S


to add here- my oil pressure gauge is almost always bouncing. i can’t tell if that’s a result of a ground, or just the gauge itself. i replaced the sender, and for one day it held pretty solid but then went back to juggling.

[sefeing]

@Tom Well, pulled the relay with the car running and just like you thought, it goes totally dark. Possibly something with the relay itself?

I don't have LED blinkers - just LED's in the cluster itself. The corners are all normal incandescent. Wonder what the next step here would be to trace this. I cleaned all the football grounds and the nuts on the back of the cluster, as well as the contacts on the ribbons as well with Simichrome metal polish.

Edit: just went back out to check the relay brand, and it's a URO. Wonder if maybe the relay is... cheap

[Tom]

@Tom Well, pulled the relay with the car running and just like you thought, it goes totally dark. Possibly something with the relay itself?

I don't have LED blinkers - just LED's in the cluster itself. The corners are all normal incandescent. Wonder what the next step here would be to trace this. I cleaned all the football grounds and the nuts on the back of the cluster, as well as the contacts on the ribbons as well with Simichrome metal polish.

Edit: just went back out to check the relay brand, and it's a URO. Wonder if maybe the relay is... cheap

URO is known for its poor quality. If it goes out when you pull the relay, that suggests to me the power is getting to it via the relay and not some cluster issue. Here's highly scientific test you can try if you have the equipment. Put the relay back in and sit in the car to watch the light flicker. Then have somebody flick the relay with their finger so see if that gets translated into light flickers. I bet it will, meaning the contact inside is not centering but rather very slightly making contact inside even with not flashing. If so, I'm thinking there's a good chance a new flasher relay will fix it. Even if the light doesn't flicker with that test, I'd still lean toward trying another. It's a URO after all. Maybe find a cars and coffee and see if someone will let you try theirs....

[sefeing]

@Tom low and behold, it was the relay! Yanked out the old URO and put in a new Wehrle, and issue solved. I even swapped them back and forth a few times to verify.

[Tom]

@Tom low and behold, it was the relay! Yanked out the old URO and put in a new Wehrle, and issue solved. I even swapped them back and forth a few times to verify.

Nice, thanks for closing the loop. That's a new one for me, so happy to learn of a new failure mode for next time.