Hey, I'm having a problem with my temp gauge. It is always at 100 its never moves and I'm not sure how to fix it, so I was just wondering if one of you could help me out thanks!

 

Is 100F the lowest temperature? If so, my initial take is that the wire at the sending unit has become disconnected or corroded, but it also could be the sending unit itself. Diagnosis is key. Start by checking the GAUGE fuse. The gauge will default to the lowest reading if the fuse is blown. The GAUGE fuse also powers the volt meter and the oil pressure gauges.

To check the gauge, disconnect the wire from the sending unit located in the driver side cylinder head. With the wire disconnected, the gauge should drop to the low side. With the wire grounded directly to the block, the gauge should max out. If this does not occur, there is a problem with either the gauge or the wiring/connections from underhood to the gauge.

The coolant temperature sending unit should have a resistance value of ~55ohms at 260F (127C) and ~1400ohms at 100F (38C) [higher resistance at lower temperatures].

 

Yes, 100 is the lowest it will go. I know the fuse isnt blown because all my gauges work but that one. I am just not sure which wire(s)? are for the temp gauge

 

I'm having the same problem with my 91 s10 blazer, it's the 4.3 engine and I don't have any sending unit on the driver's side cylinder head. The repair manual also says it's on the driver side but I've looked all over it and it just ain't there. I have a sensor located on the front of the intake manifold and there is one on the passenger side cylinder head. Can anyone tell me which one of the sensors that I do have might be the temp sending unit?

 

woops, was in the wrong area, not trying to thread jack.. mine ended up being the sender on the side of the passenger side cylinder head.

 

Hello
new to this forum. In fact this is my first forum tread ever.
I just bought my first 1989 k5 blazer this afternoon. I am making a list of things to fix-upgrade on my new project. I noticed a simiular problem on my k5 as i was driving home but i think my guage is reading about 125 and not moving. That response to your similar problem is awesome. I'll check it in the daylight tommorrow. (gotta buy a service manual this weekend)
thanks!