[Kwikfox]

Alright guys, I need some more help. When I start my car, my heat guage goes from cold, to over the hot side. I than tap my guage and it moves some more. Or I will be driving, and it will randomly switch from the middle to hot or vice versa. So what could the possibilities be? I am thinking that it might be the guages themselves. This has been happening since I got the car, but I am getting very sick of it. It makes me paranoid because my first motor overheated, and I am still paraoid about that. So what are some of the possibilities? Thanks.

 

[ITA-MR2]

My first guess is that there is a short to ground somewhere along the wire from the gauge to the temp sensor in the engine.

 

[fogjammer]

How is your heater working, and does it show any signs of overheating, gurgling or pinging? If none of these are happening, I'd look at the wiring, coupler to the gauge sender and gauge sender at the front of the motor. Maybe the sender is flakin out inside. The sender is above the alternator.

 

[Kwikfox]

My heater has no gurgling, nor pinging, but what do you mean by overheating?. I dont think my heater is having any problems. But Ill check into what you said fogjammer. I am going to be working with my alternator tmro, so I might as well check out the coupler.

 

[fogjammer]

Sorry, bro, I hit ya with some bad sentence composition. What I meant, if the heater is heating, and the engine is not boiling the coolant or showing any signs of overheating, it looks like a temperature indication problem. Some systems, depending how they are wired, will have temperature readings that will climb when the connections corrode or get loose, increasing the resistance of the connections in the wiring to the gauge. You see, there are PTC (positive temperature coefficient...resistance goes up as temperature goes up....in this system temp reading will go up with a bad connection)....and NTC or negative temperatue coefficient... which will have the opposite effect. The PTC and NTC applies to what the sender does as it heats and cools and of course the gauge is matched to the sender.
Gauges go bad, too.

 

[fogjammer]

I should have checked before posting.. sorry, but you do indeed have a PTC sender.

 

[ITA-MR2]

My post was based on my knowledge of how the gauge and sender work on our particular cars. The B+ is supplied to the gauge and is grounded though the sender. The fact that it pegs immediately indicates that the lead to the sender is probably grounded.

 

[Kwikfox]

But than what explains me tapping the guage, and than the sensor guage will move to a different location?

 

[ITA-MR2]

Fine. Replace the gauge. You might get lucky.

But - try unplugging it from the sender first. If it still pegs - it's not the gauge. If it doesn't it may be either the sender or the gauge.

I'm not going into a dissertation of how the mechanical portions of electromechanical gauges work.

 

[mrAW11]

Fine. Replace the gauge. You might get lucky.

But - try unplugging it from the sender first. If it still pegs - it's not the gauge. If it doesn't it may be either the sender or the gauge.

I'm not going into a dissertation of how the mechanical portions of electromechanical gauges work.

ditto

 

[Kwikfox]

Well I fixed the problem guys. I go to replace my alternator, I than turn on my car, and the heat guage works just fine. Since I was skeptical about it, I took it for another ride, and it still worked. So I guess my bad alternator had something to do with it maybe? Well thanks for the help everyone.

-Chris

 

[ewaustin]

Your bad alternator didn't have anything to do with it. You bumped the wire.

 

[ITA-MR2]

^^^

:werd: