1990 Volvo 240- Bizarre Temp Gauge Isssues

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Year and Model: 90 240 and 94 850T
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1990 Volvo 240- Bizarre Temp Gauge Isssues

Post by rice240 »

My temp gauge read really low for a while and then it read high, just below the red. Sometimes it would just drop suddenly. So I bypassed the temp compensating board. No change. I bought a new sensor, no change. I grounded the lead and it went high but not all of the way. IF I unplug it it goes down to cool but not to the bottom. I then grounded it to the negative battery terminal with a test light and the light came on very faint. I guess it is getting a signal from some electrical problem.

BTW I installed a TEMP gauge in the hose AFTER the thermostat so I can see that it is opening. car runs on that on at about 175.F. Where could it be picking up a signal when it's unplugged?

I give up! Help!

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Post by RickHaleParker »

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Post by 93Regina »

>My temp gauge read really low for a while and then it read high

Yeah, I bought a 1989 Volvo, which had the high read issue...previous owner who bought it a month earlier 'freak' on it, and sold it to me. He had replaced water pump and thermostat...he never told me about it.

I had a electronic tech inspect instrument panel, and he replaced some electrical parts, which mostly made this issue disappear. I installed a cooler thermostat, which was used in earlier years, but I do longer daily runs. It's not red-lining now.

I'm not concerned about it, but if a new wire was installed, from temp sensor to panel's plug, I suspect this issue might disappear.

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