1987 YJ with a 4.2L. My temp gauge stopped working. The needle does move slightly when the ignition is turned on but other than that, nothing. I cleaned the connection at the sender(little guy, driver's side, near the firewall on the head) and that didn't help at all. I also checked all my fuses, and they are fine. I loosened the guage cluster from the dash to check for loose wires and everything is secured. Any ideas? My father is borrowing my service manual so I don't have it to check the wiring at this time.
Also, what is the blue plastic cover on all the lightbulbs in the dash for?? can those covers be removed to make the gauges brighter at night?