nix1981

My coolant temperature gauge reads a little above the 1/4 mark. When I ground the lead going to the sender the gauge pegs, but only half way. I'm a bit confused. Shouldn't this peg all the way to the right? My oil temp reads low too and when I tested the gauge it pegged all the way to the right... both go up when everything is warmed up, but not much. Thoughts?

0Willcox Corvette

With the ohms wire grounded the gauge should peg full hot and when the ohms wire is left off the gauge it should read cool.

Willcox

nix1981

I'm assuming referring to the lead wire/connector being the Ohms wire. When I ground it out it goes to about the 200 mark - halfway. It doesn't 'jump' there either - just quickly but slowly (if that makes sense) gets to halfway... all connections have been cleaned with the exception of the gauges themselves. I'm including a pic of the gauge while grounded - from the Ohms wire?

nix1981

ttt

doorgunner

While the gauge is WELL-GROUNDED gently tap the lense with your fingertip to see if it will move all the way....it may be stuck...it may be defective.

I bought an inexpensive Infrared Temperature gun to check my engine temps and compare them to my gauges. The spot on the engine WHERE you point the gun will also give different readings. Read some posts on where to check the engine for water and oil temperatures.

0Willcox Corvette

Okay.. let me ask you.. does the temperature gauge move at all? Or does it always read 200. If it's not moving at all then I have to think you have a flexible pcb issue or a gauge issue.

All the possible face readings for a temperature gauge is posted below and as you can see none fit your issue. If it was a blown resistor on the gauge then it would peg as shown below, if it was a broken wire you'd be reading cool all the time, if it was shorted out at the sender it would peg all the time.

So.. if the gauge isn't moving at all then I'd pull the center cluster and take a hard look at the pcb, if it looks good then I'd pull the gauge out and test it in my hand to see the results. If the results are the same as you describe above replace the dash unit.

nix1981

When the car is off, no power it reads just under 200 as shown in the pic. When power is on (not running) the gauge goes to the left <100. When ignition is on an grounding the Ohms wire it jumps to the right, just at under 200 as shown. It does not peg all the way right. When running and warmed up it moves to just between the thick 100 line and the skinny hash line just above the 100 mark. The oil temp reads about the same - barely. Though it pegs all the way to the right when grounded. PCB? Ive been wanting to replace that anyway. A few of the lower lights are not working despite replacing bulbs etc.

ace_cobra

I have the exact same issue with a 1970. Did anyone ever sort this issue out? Its a fairly new temp gauge

**EDIT**

Fixed: ensure that the ground wire is secured properly, that was my issue.