Temp guage

[Bernight]

My temp gauge goes to hot as soon as I turn the key on. I've checked out the sending uni and replaced It. If you disconnect it the gauge still goes to hot. I assume that there might be a short in the wires or it's a bad ground wire. Any help would be appreciated.

[fourwd1]

to check the gauge, measure the resistance between terminals as follows

If you cluster has a tach,
IG-TU - approx 135 ohms
TU-E - approx 138 ohms
IG-E approx 273 ohms

for cluster w/o tach
terminals 1-2 - approx 25 ohms

the sending unit should be about 146 ohms at 140 degrees and approx 24 ohms at 239 degrees

[MC_BigMike]

The temp gauge is controlled by resistance: More resistance = high temp reading. You have a 100% direct short somewhere where the gauge signal wire has come in direct contact with a ground source.

It is very common for the wire at the temp sender that mounts atop the thermometer housing to fray. Once frayed, any exposed wire contact with the housing will send a lot of resistance to the gauge causing it to read extraordinarily high. Hopefully this is the case because the sensor is right out in the open and this could be a very simple fix.

Here are some images I found on Google that should help:





This is a very common problem. The wire is a small gauge that is just dangling around and constant vibrations cause it to sever itself. So *hopefully* this is where your issue is. Otherwise you'll gonna have to play a cat and mouse game with a multimeter to narrow down and trace out where the short is at.

Good luck!
BigMike