Coolant Temp Gage in '82
Thread Starter
Intermediate
Joined: Oct 2000
Posts: 48
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From: Katy, TX, USA
Coolant Temp Gage in '82
My coolant temp gage will only read the correct engine temperature when the heater lever is "On Heat". When I shut off the heater core the temp gage goes to pinned! When I put the heater back on it goes back to normal. Anyone experience this kind of problem? Strange.
Pro
Joined: May 2005
Posts: 745
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From: Miami Florida
not strange, ground or short. pull off the side panels and mole your way down to the switch and when you slide the lever look carefully. you should find something physically touching/ moving something else to cross some contacts
Thread Starter
Intermediate
Joined: Oct 2000
Posts: 48
Likes: 0
From: Katy, TX, USA
I double checked it. It's a new AC Control unit I put in (the kind with the new metal levers). I can't see any wires grounding or touching down there. Everything else works OK, except that darned temp gage. I'm going to try taking the heater core out of the loop and cycle the hoses under the hood to see if anything changes.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I looked at my manual. The only thing those two components share in common are the Instrument panel wiring harness. If you had to trace the problem it would be in the yellow or green wire. I think what is happening is there is a bare spot somewhere and the wire for the temp guage is touching the heater wire. when you set it to heat the wire goes live. Power through the wire thats being touched is affecting your temp guage.
There is no easy way to find this. You will have to pull out the center cluster and trace the wires. Unless you can some how get your hand on the harness and wiggle it. Look for a change.
Jim
There is no easy way to find this. You will have to pull out the center cluster and trace the wires. Unless you can some how get your hand on the harness and wiggle it. Look for a change.
Jim
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Originally Posted by Raygun82
I double checked it. It's a new AC Control unit I put in (the kind with the new metal levers). I can't see any wires grounding or touching down there. Everything else works OK, except that darned temp gage. I'm going to try taking the heater core out of the loop and cycle the hoses under the hood to see if anything changes.
Don't bother. It has nothing to do with the problem. If It pegs right in one setting goes back to correct in another is definitely electrical. Any bubba work on the harness??? Spliced for something aftermarket??? Radio maybe??. You either have a minor short or pinched some wires together.
Easiest way to find it is to trace the harness.
Jim
Thread Starter
Intermediate
Joined: Oct 2000
Posts: 48
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From: Katy, TX, USA
I had replaced the head temp sensor and checked the continuity (yellow wire) from the sensor to the gauge itself awhile back. Good ohm reading. I cleaned up all the gages of dust installed a new circuit board and dash bezel before I hooked everything up. Now, this problem. I need to find a good auto electric repair shop I think. I don't get it, the heater lever is mechanical that actuates the vacuum switch on top of the heater coil box and it's vacuum only. I wonder if it goes back to the temperature adjust lever and is turned from a vacuum to an electrical signal? From what I can tell it only sends or turns off vacuum to the hot water valve under the hood to open or close the coolant valve.
I'll try wiggling the harness and see if I can see a change. Thanks for the suggestion!
I'll try wiggling the harness and see if I can see a change. Thanks for the suggestion!
Last edited by Raygun82; Apr 19, 2006 at 12:14 AM.
