Temp gauge problems!

black t top · Nov 27th, 2014, 16:55

The coolant temp gauge on my 1989 760 V6 is refusing to move off the stop. The car has never been messed with, has 74,000 miles and 1 owner before me.

I've just replaced the gauge sender unit on the back of the engine block, but the gauge itself is still dead......I've given the top of the dash a whack too, in case it was stuck and it didn't make any difference.

My questions are:

1) If I remove the offending gauge from the cluster, is there any way to test the gauge for function my applying a signal to it directly? If so how....??

2) If I get a 2nd hand cluster, will any 740/760/940 temp gauge fit, from any engine type, or does it specifically need to be from a 760 V6

3) Other than the gauge being kaput, is there anything else you guys would suggest I try, the wire doesn't appear to be damaged anywhere.

cheshired5 · Nov 27th, 2014, 20:00

On mine, with ignition on, the coolant sensor plug has a 5v signal feed.
I wouldn't have thought things have changed too much since yours.

Forrest · Nov 27th, 2014, 22:58

If you remove the plug from the sensor and bridge the two connectors on the lead does the gauge move?

bob12 · Nov 27th, 2014, 23:24

On the basis that it is a cluster made by Yazaki (most, if not all later 760's are) a gauge from any VDO cluster will not fit. I assume that a Yazaki gauge from a 940 (at least earlier ones) will fit, but if no further replies to this thread you will have to check it visually.

black t top · Nov 28th, 2014, 09:47

Forrest- It never occurred to me to try that......good idea! I'll try bridging the connections on the plug and see if it moves....I take it if it moves then the new sender is faulty, if it doesn't move it's the gauge? Bridging the connections won't damage anything will it?

Bob- I assume it's the Yakazi version...I was hoping a VDO gauge was a straight swap into my cluster.....I'll pull the cluster at the weekend and visually check it out, but I'm 99% sure it's a Yakazi unit.

bob12 · Nov 28th, 2014, 11:55

Quote:

Originally Posted by black t top

Bob- I assume it's the Yakazi version...I'm 99% sure it's a Yakazi unit.

Look at the lower trip odometer .. if it's got divisions in the face plate between the every number comprising the hundreds and tenths it's a Yazaki. If not it's a VDO.

Nov 27th, 2014, 16:55	#1
black t top Junior Member Last Online: Sep 11th, 2019 10:34 Join Date: May 2013 Location: Glasgow	Temp gauge problems! The coolant temp gauge on my 1989 760 V6 is refusing to move off the stop. The car has never been messed with, has 74,000 miles and 1 owner before me. I've just replaced the gauge sender unit on the back of the engine block, but the gauge itself is still dead......I've given the top of the dash a whack too, in case it was stuck and it didn't make any difference. My questions are: 1) If I remove the offending gauge from the cluster, is there any way to test the gauge for function my applying a signal to it directly? If so how....?? 2) If I get a 2nd hand cluster, will any 740/760/940 temp gauge fit, from any engine type, or does it specifically need to be from a 760 V6 3) Other than the gauge being kaput, is there anything else you guys would suggest I try, the wire doesn't appear to be damaged anywhere.

Nov 27th, 2014, 20:00	#2
cheshired5 Premier Member Last Online: Dec 26th, 2021 13:42 Join Date: Dec 2013 Location: Crewe	On mine, with ignition on, the coolant sensor plug has a 5v signal feed. I wouldn't have thought things have changed too much since yours. __________________ 2002 S60 SE D5 Manual 209000 miles

Nov 27th, 2014, 22:58	#3
Forrest VOC Member Last Online: Today 18:17 Join Date: Feb 2008 Location: Gloucester	If you remove the plug from the sensor and bridge the two connectors on the lead does the gauge move?

Nov 27th, 2014, 23:24	#4
bob12 bob12 Last Online: Today 18:50 Join Date: Aug 2006 Location: Woking	On the basis that it is a cluster made by Yazaki (most, if not all later 760's are) a gauge from any VDO cluster will not fit. I assume that a Yazaki gauge from a 940 (at least earlier ones) will fit, but if no further replies to this thread you will have to check it visually.

Nov 28th, 2014, 09:47	#5
black t top Junior Member Last Online: Sep 11th, 2019 10:34 Join Date: May 2013 Location: Glasgow	Forrest- It never occurred to me to try that......good idea! I'll try bridging the connections on the plug and see if it moves....I take it if it moves then the new sender is faulty, if it doesn't move it's the gauge? Bridging the connections won't damage anything will it? Bob- I assume it's the Yakazi version...I was hoping a VDO gauge was a straight swap into my cluster.....I'll pull the cluster at the weekend and visually check it out, but I'm 99% sure it's a Yakazi unit.

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