Alright, I'm hoping someone can provide a bit of insight here. So far I've replaced the headlight switch, the bulb failure sensor, the in-dash main headlight relay, and the step relay under the hood. As added insurance I just put new bulbs in, but I get no voltage at the connection. It doesn't look like any ground wires are loose... All other lights function just dandy. Any suggestions?

Karl

 

Clean the ground wires connectors, the ground block, the bolt, and where the bolt mates to the body panel. My 740's both exhibited lots of weird headlight issues (different brightness, ignition cut out when switching to high beams, windshield wipers coming on when turning on headlamps... Seriously, all of those - no joke).

When I cleaned the ground blade, plug and block, all those went away.

I would recommend taking the time to go around all of your connections and clean them, 21 years is a long time to expect unsealed electric connection to remain trouble-free.