Coolant temperature problem

[thepoloplaya]

My temp gauge goes all the way up and stays up as soon as I turn the ignition on. Im running an m50 with full standalone, not utilizing any of the factory harness from the c101, but made my own harness. The strange part is, even when the c101 is disconnected completely from my harness the gauge still goes all the way up and stays there.

Please advise.

[nando]

sounds like the gauge sensor isn't hooked up.

[dkbmxer002]

mines been doing the same thing... before i even turn the car on it jumps to full hot..



problem is mine is a stock m42....
i've tried tracing wiring to see if it had a bad connect, nothing.
checked fuses and relays, nothing.
replaced gauge coolant sensor, nothing.
put a ground strap on the head, nothing.
tightened the nut on the back of the cluster, nothing.

[bmwman91]

1) Maybe the coolant gauge is busted

2) Did you mix up the oil pressure switch & coolant temperature sender connectors (I did this on my M42 once...oil light will slowly light up as the motor warms up)? They are on the same wire loom and can be mixed-up.

3) Sometimes the wire breaks at the connector. Pull back the rubber boot and make sure that the wire is fully intact at the temperature sender. Check where it is crimped into the terminal.

4) Check C191.

You should see < 10kOhms between the sender output & ground. Start at the sender and work up through the harness. If you get to a point where the resistance is very large, then you passed a break in the wire. Get out that multi-meter!

[dkbmxer002]

where is it crimped into the terminal? also what is c191?