I have a temperature gauge that is stuck on maximum. Has been since I bought the car 3 weeks ago.
I had an idea that I should start by checking the sender in the cylinder head, but today I observed that the instrument is stuck on maximum with ignition off as well.
This brings me to the conclusion that the instrument must be defect.....

Am I overseeing other failures here before I just run along and try to get hold of a new instrument.?

 

No, could easily be that the meter itself is just jammed up there.

Take the bezel off and move it with your finger, see if it begins to behave.

 

Good idea, will remove and test that.

 

Good tip, it was jammed actually.
Managed to loosen it and assembled everything. Gauge worked fine.....but then on the third start attempt it jammed again....
Seems like it jumps to maximum when the starter is engaged, but it dropped down fine until the third attempt.

Obviously need to do something with the needle or the surface to make sure it cannot jam in that position.....

 

Yup. It's designed to do that. It's wired to the ignition switch, which grounds the sending unit wire when in Start to simulate high temp. It's the same thing as the "bulb check" function in cars with warning lights and no gauge.

 

I have pulled the gauge, but am scratching my head how to fix it.
Is this a known problem ? Maybe just wear in the gauge making the needle jump over the edge and get stuck.....

 

Looks like the stop pin is broken off, letting the pointer get up farther than it's supposed to.

 

Just get another gauge...

 

Ahhh.....so there should be a stop pin...that explains it.....

 

Probably the easiest solution.....it's only 40 USD.....

 

I don't know if this will last, but at least I will try this as a start and then if it doesn't I will order a new gauge.
I glued some epoxy to the part of the gauge where the needle hits the edge and it works so far....