temp gauge sender

[mars]

My temp gauge doesn't move when the car is running. I'd like to eliminate the possibility that it is the sender before I pull the cluster out.
Can anyone tell me where the sender for the temp gauge is?
Car is an 89 325is.

[slo325i]

I believe it's the brown sensor on the t-stat housing but i'm not 100% sure.

[scabzzzz]

bump
Im having the same issue. I think this part is the culprit. Can anyone confirm with the OP?
Part number: 12 62 1 710 512
Number 12

[jlevie]

A simple test the will tell whether the cause is in the sensor or cluster is to disconnect the temp sensor and see that the needle is at the bottom of the blue with the ignition on. Then ground the sensor plug which should drive the need to to full hot. If either of those tests fail, the problem is in the wiring, or more likely in the cluster.

The common causes of an inop temp gage are a bad SI board and/or a bad connection where the temp gage mounts to the main PCB in the cluster. Re-flowing solder onto the pad is the fix for the contact problem. Replacing the batteries in the SI board, or replacing the board, is the fix for a bad SI board. If the batteries are bad and haven't leaked onto the SI PCB, you can replace just the batteries. But if there is corrosion of the PCB you need a new board.

[87-325ic]

your posts never fail. thanks so much.,

btw, OP, most of the time its a problem with the cluster, and you can usually smack the dash and it will pop up to the right temp.
the sender is pretty cheap to replace too if needed.

[scabzzzz]

I think I'm going to just order another sender anyways.
Regarding my issue, I've smacked the cluster and it doesnt seem to be that. I had a cluster do that once, and it popped up and down. This one acts like its either the Si board or the sender on the t-stat.
Thanks Jim!!!