No High Beam Anymore, Low Beams Work Fine

[Big Tom]

We recently took the truck into the dealership to have the rear fenders completely replaced, shortly after they were done we noticed the high beams on the truck no longer work. Not sure if those two events are somehow tied together, might be complete coincidence but thoughtd I'd mention it anyway.

 

 

But anyway we sortof played around with the lights trying to figure it out but we're not sure what's going on. When we start the truck and turn on the lights the low beams are working fine, when we click on the high beams the lows go out but nothing happens for the highs. We replaced the bulbs, they looked good prior but did anyway and the problem is still there. We disconected the plug for the lights and with a test light checked both ends and each side had power? Didn't have a voltmeter to check actual voltage but the light did come on. I wasn't sure if having the bulb disconnected if that's typical or not?? Almost seems odd I would typically expect to see one wire ground the other power unless maybe the lights have a switched ground and normally have power to both wires?

 

We checked the fuses under the hood, none seemed to be bad... we moved around the relays also under the hood thinking maybe one was for the highs but same situation.

 

Any ideas where we can start looking? The steering column switch seems to click and feels fine but is there anyway to test if somethings wrong on the switch itself? I mean it's obviously trying to switch since the low beams go out

[dhansell22]

Ever find out what the problem was? I have the same issue on my '05. It happened a few years ago and under warranty they replaced the multi-switch and the BCM. Now it is happening again. I would say it's not the switch because it lights up the high beam indicator on the dash.