'86 C10 temp gauge

[79Scott]

Hey guys,
The temp gauge in my '86 Silverado stays pinned at max temperature at all times, I am guessing the coolant temp sensor is bad? Truck runs fine and doesn't overheat or anything.

Thanks

 

[80BrownK10]

Pull the wire off the sensor and see what it does.

 

[Dutch Rutter]

What Brown said above. Usually if it's pinned at max your wire is pinched or grounded out. If it's hard zero then most times your gauge or sensor is fubar in some way.

By pulling the wire that'll tell us whats what, if it stays the same you have a grounded wire. If it drops then it's one of the other.

 

[79Scott]

Guys,
I pulled my temperature sensor (see pics below). The connector that is on the existing sensor is different than any of the replacement sensors I have found. Have any of you run into this? If so what replacement did you use? Thanks

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[bob seifert]

Thats a temperature sensor but not to you temp gauge. It controls the solenoid in you carb that its attached to. I believe to deliver more fuel at idle while cold.

 

[79Scott]

Dang,
Where is the actual temp sensor? I looked allover the intake last night and didn't see anything that looked like a temp sensor....

 

[Dutch Rutter]

Dang,
Where is the actual temp sensor? I looked allover the intake last night and didn't see anything that looked like a temp sensor....

They are usually placed between cylinder 1 and 3 on the side of the cylinder head. See the circled area of the picture. It should have a dark green-ish wire (color fades overtime) connected to it.

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Should be able to just unplug the wire from the sensor. If pulling the sensor there will be coolant behind it.

 

[79Scott]

Ahh, Thanks. I appreciate it

 

[79Scott]

The temp gauge is pinned at max reading (Actually is to the limits of the gauge) Replaced the temp sensor and no change. Followed wire to the fire wall and all is good. Short of checking the wire from the firewall to the gauge I assume the gauge may be bad?

 

[79Scott]

Hey Guys,
Just an update on this. Replaced the temp gauge and the sending unit and my gauge still does not work. Traced the green wire from the sending unit back to the fire wall and that all looks good. Any suggestions of what could be wrong?

Thanks

 

[Dmack]

Possibly the printed circuit on the back of the gauge cluster.

 

[79Scott]

I thought that maybe too, but it appears to be in good shape fwiw

 

[idahovette]

Check the circuits out with a continuity tester

 

[F-64]

What is the resistance between the green wire at the gauge and ground? Does it change as the engine warms up?