wacky coolant temp gauge

[scobaru]

so the coolant temp gauge on my e30 will jump back and forth and is almost never accurate. I've heard the solder just becomes old and will just wear away. I have the cluster out since I'm doing some other repairs does anyone know exactly needs to be fixed or re soldered ?

[redhatpat]

Have you confirmed the sensor is good?

[wagonizzle]

Check and see if the ground nut on the gauge is tight...

[scobaru]

I'll check the ground nut on the gauge. and i haven't confirmed the sensor is good but on the last 3 e30's I've looked at/owned they all had the same problem. I know its some what a common problem on E30's thats why I though I'd look. if the sensor is bad it'd throw really crazy signals since the gauge shoots back and forth which wants me to believe its more of the cluster problem but i'll take a look

[dougsic]

Check and see if the ground nut on the gauge is tight...

This is the problem. The two brass nuts on the back of cluster ground it. They work loose and the temp gauge and/or the fuel gauge becomes jumpy.

[scobaru]

I took the cluster out and I found my problem circuit board needs some soldering

[gearheadE30]

I've never seen a trace burn there before...

[bignate948]

i have the same problem with my gas gauge. where are these brass nuts that ground it?

[txleadfoot]

The brass grounding nut was the issue with my jumpy temp gauge. Now it reads correctly. There is one nut in this photo:

[JinormusJ]

Bumping this because I have a question; temperature gauge likes to flop around; when replacing the nut (because mine fell and is no where to be found; does it have to be brass? Or does it just need a nut there?

[dudecati]

I just replaced mine as it was missing too. I went to the local hardware store got a nut AND lock washer, tightened it all up and it works like a charm. The replacement hardware was not brass.

Bumping this because I have a question; temperature gauge likes to flop around; when replacing the nut (because mine fell and is no where to be found; does it have to be brass? Or does it just need a nut there?

[JinormusJ]

Sweet; exactly what I did, and mine is not brass either; was just about to run out to a different local hardware store and try my luck for brass fittings, but since material is not a necessity, I'll make due

Thanks

[noid]

On my first E30 my temp gauge would jump around erratically, it ended up being the oil pan to body ground.

[izickc]

i am having this issue too,,,, i have replaced the cluster and its still happening, where is the sensor that connects it to the engine located?