I have a 89 xj with the 4.0 with a minor problem, my temp gauge is pegged out but the engine is hot .Sending unit has been replaced according to the guy that I bought the jeep from.Also the oil pressure gauge is jumping around.Can I put manual gauges in it and leave the others tied in to the other gauges.

 

The stock gauges are run by the stock sending units. The stock sending units will NOT support a second gauge, temperature or oil pressure. You can always put a "T" where the oil pressure sending unit is located and run a gauge from there too. Either a mechanical gauge or a second sending unit for an electrical gauge.
Don't have any suggestions about the temp gauge though, sorry!

 

Is it possible that the sending unit is for a light and not for a gauge.

 

Went to the auto zone site but really can't see much difference between the two http://www.autozone.com/selectedZip,.../selectZip.htm Could possibly be the wrong one Shoot for 11.00 it might be worth a try.

 

might be the cluster... bad connection. if the oil PSI gauge flickers you might want to start looking for a new (used from a junk yard) gauge cluster

 

Been talking to the guys at orilies and they said according to there computer that they only carry the sending unit that is for the light and that one takes more ohms for it to read the temp right.

 

There are different sending units that are used for gauge or light applications. But they look different one has a single wire and the other has a two wire hook up. IIRC Try this as an example. May be the wrong year for your application.
http://www.partsamerica.com/ProductL...pe=417&PTSet=A

 

He is looking at the temp sending unit. According to the auto zone pics(I thought you could see their pic better) they LOOK similiar but are not the same. So it is possible that someone put the wrong sending unit in. Around here they hire high schhol kids to work the counter that is why I look up my own part # before I go to parts store. I figure that gives me the best shot at getting the correct part.

 

I usually order from NAPA and pick it up at the store. Napa's part had no pictures at all to look at but a generic sender. So that's why I used the link I did use. Didn't know he wanted the Temp Sender too. Well once you access that link you can search for different stuff. Hope he solves this problem of the gauges. I think it would be hard to drive w/o any input from gauges.

 

Also there maybe a short. I know in my Charger when the temp wire got shorted against the intake it would peg out. Might be different with the XJ's, but I am not sure.

 

When you start talking about Chargers you are outside my area of knowledge. They may be similar since they are both from the Chrysler family of fine vehicles.