Coolant Temperature Gauge Sender Screwed Up

stroup · Tue, Apr-06-2010, 01:32:45 PM

Just got the car (1995 M3) running after a head gasket change and all seems well except my temp gauge.
IT
-is stuck high in the overheated position
-with ignition turned the needle goes up to red and light turns on
-with engine running the needle goes up to the same position but the light does not turn on
MIND YOU THIS IS WHEN THE MOTOR IS COLD, I'm not that big a noob lol.

so according to Bentley
"If the gauge needle reads too high when the engine is cold, remove the harness connector from the sender. Turn the ignition on. If the gauge needle position does not change, the wiring or the gauge is shorted to ground If the gauge needle drops, the sender is faulty and should be replaced."

This is my problem, after this test the needle position does not change (meaning goes back to same high position, basically the wiring or the gauge is shorted to ground). Bentley did a fine job of diagnosing this problem but fails to explain how to FIX IT WTF.

My one possibility that I can think of is that maybe i got the two grounds on the head cover (near ignition coils coming from mounting bolts) placed incorrectly. Does anyone know the proper placement of these grounds? Or how to fix the gauge would be sweet as well.
Thanks!

Volcom8190 · Tue, Apr-06-2010, 05:55:26 PM

You switched the wires between the 2 senders, swap them around

stroup · Wed, Apr-07-2010, 02:50:21 AM

tried it, got the same result

Tue, Apr-06-2010, 01:32:45 PM	#1
stroup noob Join Date: Apr 2010 Posts: 5 Reputation: 0 Location: Greensboro	Coolant Temperature Gauge Sender Screwed Up Just got the car (1995 M3) running after a head gasket change and all seems well except my temp gauge. IT -is stuck high in the overheated position -with ignition turned the needle goes up to red and light turns on -with engine running the needle goes up to the same position but the light does not turn on MIND YOU THIS IS WHEN THE MOTOR IS COLD, I'm not that big a noob lol. so according to Bentley "If the gauge needle reads too high when the engine is cold, remove the harness connector from the sender. Turn the ignition on. If the gauge needle position does not change, the wiring or the gauge is shorted to ground If the gauge needle drops, the sender is faulty and should be replaced." This is my problem, after this test the needle position does not change (meaning goes back to same high position, basically the wiring or the gauge is shorted to ground). Bentley did a fine job of diagnosing this problem but fails to explain how to FIX IT WTF. My one possibility that I can think of is that maybe i got the two grounds on the head cover (near ignition coils coming from mounting bolts) placed incorrectly. Does anyone know the proper placement of these grounds? Or how to fix the gauge would be sweet as well. Thanks! Last edited by stroup; Tue, Apr-06-2010 at 01:36:35 PM.

Tue, Apr-06-2010, 05:55:26 PM	#2
Volcom8190 Registered User Join Date: Aug 2008 Posts: 53 Reputation: 0 Location: Cary/Charlotte	You switched the wires between the 2 senders, swap them around __________________

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Wed, Apr-07-2010, 02:50:21 AM	#3
stroup noob Join Date: Apr 2010 Posts: 5 Reputation: 0 Location: Greensboro	tried it, got the same result