OHC Temp not working

My OHC temp is not working. The compass works but not the temp. Any ideas?

Check the sensor in the front of the vehicle.

Does it read anything at all? Zero?

Yes it says 0C. Where is the sensor at the front. Also what is the thing on the OHC that looks like a very small security camera globe? It is a 93 XJ

Sounds like the sensor is damaged. It's the thing on the front crossmember just behind the front bumper. You can get them by the handful at junkyards if you want to test.

The dome thing is for the keyless entry system. It used infrared and you had to be right next to the jeep, pointing directly at the sensor.

Oh... Well I never got a keyless remote so im sure that doesnt work anymore.

OC means Open Circuit. The OHC is smart enough to display that - it will also display SC if the two wires are shorted. Check the connector with the violet/green and black/light blue wires around or under the front end of the power distribution center. Unplug it and use your multimeter on the 20k ohms scale to check the wiring leading down past the battery - if it reads as open, the problem lies in that wiring harness or the sensor itself. If it reads as a value in the 10k range or so (may be different depending on your weather) you have a problem in the engine wiring harness, interior wiring harness, cross body wiring harness, or overhead wiring harness.