Don't give up so fast there knoiwn issues with the gauge cluster.
Takes about 6 screws to remove on connector drivers side rear of the cluster.
Take it to the kitchen table and dissasseble slowly and you will see the sorry copper circuit sheet that everything gets its power from. You need to clean all the contact points with a rubber eraser. Polish and clean reinstall and check it out.
If you still have problems with a gauge then chase the sending units (oil, temp)
The temp sensor on the engine for the gauge is on the cylinder head drivers side rear single wire connector purple.
The oil pressure sending unit is on the passenger side near the distributer and can be sourced at most parts houses <$25.
Work with it and save some big bucks for other mods. If not I have the wire colors at work on another computer I will post later if someone else doesn't post up earlier.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
Have you bothered pulling the gauges and checking for power? or fuses? Or check auto zones site. Free wiring diagrams. Could google image search it too and find what you're looking for. Or spend $20 on a chiltons or Haynes manual. Which you'd be dumb not to have with an old jeep. So....plenty of options.
1990 Jeep Wrangler YJ. 2.5L. Bone Stock, mostly.
"I'd have more money for upgrades if it didn't break every week."
Just my opinion, and not meant to offend ANYONE! As a former mechanic, I have seen plenty of hack job "repairs" done by owners who think they know what they are doing. Do us all a big favor (especially future owners & future mechanics who may have to fix your "repairs") get yourself a PROPER repair manual and follow it. Get one that has EWD's for your model an learn how to read them. Then do what you are comfortable doing and take it to a shop (with the manual) for things you are not comfortable with. It will save a ton of headaches in the future for everyone involved. My $0.02
'89 Yes it's a Junker, 2.5l, 5 speed, Big balding tires, Some kind of lift that makes it really hard to get in to. Oh well, it runs.
I've already taken the gauge cluster out and tried cleaning the connections, checked the fuses and inspected it for any corrosion or damage. Put it back in and still nothing. I bought a haynes manual as soon as I bought the Jeep (I have one for every vehicle I own). I did trace the wires and from what I've been told, I followed them to the right place. I'm very familiar with forums and do research before posting. I just can't think of anything else it could be...
Sounds like you will need a meter or test light. There are at least two hot leads that go to the cluster. If nothing at all works I'd suspect a fuse or bad ground. I don't remember how many grounds there are.
The voltage gauge just has a keyed hot and ground. If that works and not the rest it could be senders. The clock is hot all the time and has its own +12v line.