temp gauge problem

[-Jack-]

I've got a '97 mounty w/ 160k miles. Recently, I would get a "check gauge" light and the gas gauge would drop to zero. After a short while the light would go out and the gauge would work again. This has not happened for a week or two. But, starting yesterday, I got a red "check gauge" light and the temperature gauge pinned itself past the highest temp reading and has not gone back to normal. I havent checked my hoses or radiator for leaks, but I dont think that I am overheating. I think its electrical.

Any ideas?

 

[ma96782]

If you got a thermometer (laser kind) you could "shoot" the hoses and check the temps. To confirm your, "I don't think it's overheating."

Aloha, Mark

PS...............May not work on your vehicle...........Cheap Test for the temp gauge (annalog type) sending wire:

KOEO...........disconnect the wire and ground it........the gauge will peg on the hot side........disconnect wire from ground and it will return. IF NOT, something is wrong, check along the length.

Sender unit itself is less then $20.......and easy to replace. Don't put too much goop on the threads......it grounds through the threads.

Aloha, Mark

 

[Turdle]

i would replace the thermostat for sure, they can stick.
Look also at the wiring to the coolant temp sensor while you are there.

 

[-Jack-]

I would be surprised if the gas gauge problem was a complete coincidence. It seems to me that the two are related somehow.

Could it be something with the wiring of the gage cluster?

 

[NHale623]

I had a very similar problem with the temp guage on my '95. I could get in the car in the morning, turn the ignition on and the temp would read half scale. Regardless of the outside temperature.

If I rapped the cluster with my knuckle, the temp would go back down to where it belonged. The problem ended up being in the instrument cluster, where the guage was plugged into the printed circuit board. To confirm the problem was in the cluster, I removed the bezel from around the cluster, pulled the cluster out from the instrument panel as far as I could, and turned the car on. I was able to make the temp needle deflect by pressing on the circuit board in back of the instrument cluster.

To fix the problem, I disassembled the entire cluster, cleaned and tinned the pins on the back of each guage and cleaned each of the corresponding contacts on the circuit board.

Hope this helps.

 

[-Jack-]

FYI - The problem ended up being the coolant temperature sender unit. $6 part and 4 minutes to replace once I had the correct tools. I spent an hour on it before I finally gave up and went to the hardware store for the correct size 3/4" deep socket & 10" extension. The bolt for the ignition coil mounting bracket gets in the way when trying to use a wrench.

 

[Turdle]

I was wondering where the fuel gage came into play?You mentioned it in your second post
Gald you got it fixed

 

[-Jack-]

I was convinced that the two gauge problems were related. But, it appears now that they werent. I am clueless about the fuel gauge. It hasnt given me any problems for over 2 weeks now. Maybe its a loose wire somewhere or gas tank sending unit Unless it starts acting up again I am not going to touch it.