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Old 11-13-2007, 09:07 PM   #1
Hoss72
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Temp Gauge Problems

My truck's Temp Guage sits on HOT HOT all the time and I mean all the time . Today I had to do some stuff on it so I installed a new temp sensor. while I had the Anti-Freeze drained I decided to change the thermostat, Water Pump and all the hoses. So what am I missing and is there a EASY way to check my water temp gauge without removing the dash. Any information you can give me would be great.
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Old 11-13-2007, 09:14 PM   #2
John H.
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Re: Temp Gauge Problems

Sounds like you may have a bad temp sending unit or the wire is grounding itself pushing the gauge to Hot. The sending unit acts like a ground and the hotter the truck gets, the more the ground side works pushing the gauge which has positive power when the ignition is turned on. Typically, if there is a short, the gauge will go to HOT immediatley after your turn the ignition on.

1. Make sure you have a sending unit for a gauge system and not the light.
2. Make sure the wire is not grounding itself.
3. Might be a bad gauge?
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Old 11-13-2007, 09:18 PM   #3
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Re: Temp Gauge Problems

It could be a bad guage... like John H. said....George
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Old 11-13-2007, 09:18 PM   #4
72BLUZ
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Re: Temp Gauge Problems

You May Have A Bad Diode On Te Back Of The Gauge!!!!
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Old 11-13-2007, 09:33 PM   #5
Hoss72
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Re: Temp Gauge Problems

It was even on HOt Hot when I had the battery disconnected.Is there a way to check the gauge Can I buy a temp gauge and put it in. or will I have to replace the circuit board . I know lots of questions thats what a newbie does.
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Old 11-13-2007, 09:44 PM   #6
byrd
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Re: Temp Gauge Problems

unhook the sending unit wire, with the key on the gauge should lay over on cold, if you ground out the wire it should read past hot. If it responds to unhooking it, the resistor on the back of the gauge is most likely the problem
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Old 11-13-2007, 09:45 PM   #7
John H.
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Re: Temp Gauge Problems

Has the gauge worked before or is the gauge new to you? From what you have told us, it looks like it might be a bad gauge. With my previous Corvette's and GTO's, the sending unit GM sells today or the one at NAPA does not give an accurate read on the gauge as it is not calibrated to the old gauges. Try to get a used sending unit for gauges.

The gauge style sending units have a button on the end and not a push pin the looks threaded.
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Old 11-13-2007, 09:51 PM   #8
Hoss72
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Re: Temp Gauge Problems

It has read Hot since I got it in September. I will disconnect the wire and if that doest work I will try to find me a new gauge. Thanks for all the help.
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Old 11-16-2007, 07:11 PM   #9
Hoss72
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Re: Temp Gauge Problems

Well 72Blue you were right it is a bad Diode, I had it checked today...thanks
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