Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Re: CJ Headlight Testing ? - Need help before 2pm tomm
When you say that you have power at the switch, is that testing with a voltmeter, with the headlight switch off?
In that situation you could have very high resistance between the fuse box and the switch, and still read battery voltage.
Also, in that situation, if you pull the switch on, your voltage reading will drop way down.
If that's the case, it's a connection from the fuse box to the switch.
The '78 wiring diagram shows that the wire that feeds the switch comes from a splice that also feeds the horn relay, the ignition switch and the brake warning light. If you're having trouble with those too, the problem is from the fuse box to the splice.
If the lights are the only thing screwing up it almost has to be the connector that plugs into the switch. BTW, the splices I looked at were crimped with a sleeve, and looked pretty secure, but I soldered them for good measure.
Also, I had a problem with one of the accessory lines that turned out to be in back of the fuse box. There are regular right-angle female spade connectors on the wires that plug onto male spades on the fuse box. On this particular wire the female connector was loose on the male connector. It would make contact some time, but lose it going over a bump. I just squeezed the connector with pliers until it was a tight fit again.
You could have a similar problem - enough contact area to register on the voltmeter, but not enough to pass the current necessary to light the bulbs.