Temp gauge on the fritz

2001, 4.0, AW4, 4x4, 191,000 miles. After driving long enough to reach normal operating temp, between 195-205, if I shut it off long enough to go get a cup of coffee, when I restart it the gauge stays at the first line past 100. Sometimes while driving it will quickly go up to normal operating temp for a few minutes, then quickly fall back to the first line past 100. It did it tonight on my way home from the store, I popped the hood and just wiggled the connector on the sensor that goes into the thermostat housing and the gauge immediately went back to normal operating temp. I assume that's the coolant temp sensor. Is that most likely my problem?

Sounds like the coolant temp sensor (which is the one you were wiggling) is on it's way out. You may try unplugging it and cleaning the connector with some electrical parts cleaner, then put some di-electric grease on and plug it back up before buying a new sensor. If that doesn't solve it, a new sensor runs $20-30 locally.

Just replaced mine (again) last week for similar symptoms. I don't recommend BWD...went through a couple of them. Bought one from Napa this time in hopes that it will last longer...

UNCC_99XJ said:

You may try unplugging it and cleaning the connector with some electrical parts cleaner, then put some di-electric grease on and plug it back up before buying a new sensor

Click to expand...

This fixed the sporadic readings on my 98 and has worked perfectly for the last few thousand miles.

When my 89 sender failed it read about 30-35 degrees hotter than it should! My new NAPA sender reads about 10 degrees too high, I'm thinking of adding a resistor so the gauge agrees with my temp. gun reading.