Problems As Always

Holidays Are Here And So Are The XJ Problems

1. Need New Reservoir Cap For Overflow Tank. Went To AutoZone And Kragan And Couldnt Find A 16PSI Cap. Where Do I Aquire One?

2. My Brake, 4WD, And Lock Light Come On And Off W/O Being Engaged. Is This From A Bad Ground Or Because My Circut Braker/ Fuse Panel Is Filled With Dirt/Mud/Grit/ETC?

3. Just Replaced Oil Sender Unit About 1K Miles Ago And Now My Oil Pressure Gauge Is Cranked Up Above 80. Is The Unit Bad Already Or Is It An Intermitten Problem?

2 & 3 sound like ground, to me.. Do you have a dealer by you?Thats for #1

I order my caps from Quadratech, $5. I usually buy an extra overflow bottle and cap to keep on the shelf. Not the best quality but they work well enough.
Cleaning the cap out with hot water and then letting them soak in Vinegar (overnight) often removes the buildup that causes most problems with the cap.
Usually when indicator lights come on when they aren't supposed to, it is a ground path problem. One light can't find the correct ground. so it tries to ground through another lamp. There is a ground under the shift cover (if I'm remembering my model year right) behind the drivers side kick panel and another under the dash (drivers side) next to the courtesy lamp. All have given me grief on occasion. The contact strips for the instrument cluster are a known trouble spot, the copper stripes corrode. They clean up with an ink eraser rather well. The harness to the shifter can be another trouble spot, the splices get wet/corroded and ground out.
Unless I'm mistaken the oil gage goes to the top when the wire is removed from the sending unit, you may have a bad contact someplace. Oil on the sender connector? Or a loose fit at the connector.