92 Astro electrical question:

Hi all, My 92 Astro van has factory fog lamps controlled by a sliding switch on the dash (factory install). The lamps don't work, but when you slide the switch to the on position you can hear a relay clicking under the left side of the dash (where all the other relays and fuses are). The fuse in the block is good (tested out of the block), the relay is obviously doing something (making noise anyway) and the lamp bulbs themselves check out OK with a continuity tester when pulled from the light housing and unplugged from the harness. Is it likely that the relay could be working on the 'switching' side but not delivering power to the output side of the relay? Anything else you would look for besides tearing out the wiring to check for open shorts in the harness (I'd just live without them rather than tear out the harness)? Bad ground on a rust-free vehicle at the lights themselves? Is this a common problem with these things (first Astro I've had)?

Thanks for reading, next round is on me.

Cheers, - Jeff G

Bubba Kahuna wrote in rec.autos.tech

Yes the relay can be pulling in and the contacts inside not making contact. However, use a test lamp or a voltmeter and starting at the lamps check for voltage. If you are getting 12 volts to the lamp then you have a bad ground. If you are not getting it, follow the wiring harness back to the next junction point. Keep moving back until you find a point with voltage. If you find a junction that has voltage, then the break is either at the junction itself or in the wire between the junction and the lamp. Also check both the input and output side of the relay for voltage. It will take a little while to check it out, but this really should be fairly easy to test.