On my neighbor-buddy's 94 Isuzu Rodeo (v-6 manual), I fixed a shorted wire in the transmission tunnel with worn off insulation a few months back. Up to that point, he had no turn signals, no front marker lights (I think), and no reverse lights. His cruise control didn't work either until I fixed that wire.

A few weeks later, his headlights stopped working.

If he holds the high beam stalk in the flash-to-pass (it's broken and hasn't switched the high-beams on and off since 6 months ago), the headlights illuminate.

I checked and the relay is clicking and feeding voltage. However, there is 12V to ALL of the headlight leads, including high and ground.

I'm leaning towards a bad switch since it stopped working to switch highs and lows on, but given the relay.... I don't really know what to look at next.

Here's what my thoughts are right now:
Find and check ground points for headlights and marker lamps.

Pull sidemarker fuse and see if anything changes at headlamp terminals.

Check switch for shorts.

Pull relay panel, check for shorted wires. (but this would blow the 15amp headlight fuses)

Cut ground wire at lamp, cap hot wire, run new ground to lamp. (worst option)




Does this scream bad grounds, or is it just me? I don't think it's the switch, and I swapped an identical relay from another system with no change.

Thanks fellers!