Is it just me?????

[Surfcityred]

Am I the only one having this problem:

I upgraded my headlight bulbs to a whiter, higher wattage set. They went in easy enough and then I realized that when the high beam indicator light is "on" my low beams are on. When I switch to the low beam position (indicator light "off") my high beams are on. Everything is ass-backwards. At first I thought the bulbs were bad so I switched back to my old factor bulbs. The reversed indicator light deal is the same even with my factory bulbs back in.

I know there must be some easy fix either with the selector switch, some control module somewhere or some other hocus pocus electronic reset but I have no clue what to do. I called my Hummer dealer and the service department guy gave me a bunch of double talk.

[f5fstop]

Did it work correctly before you replaced the bulbs?
I cannot see how just switching out the bulbs would cause this problem.
The high and low beams are directly controlled by the BCM depending upon input from the switch on the steering column.
This signal from the switch is what the BCM uses to determine if the high or low beams should be on. To turn on the low beams, the BCM grounds the HDLP relay, allowing current to flow to the low beam bulbs. A ground path is supplied for the low beam filament, through the HI/LO Relay, that is not energized by the BCM.
When you go to HI beams, the H/LO relay is energized supplying a different ground path, allowing the HI beam filaments to be grounded. If the BCM lights up the HI beams, it then supplies a command signal to the I/P module via the Class 2 serial data link.
Only thing I can see that could possibly cause this problem would be the BCM or the IPC. Even if the switch was bad, I can't see how this would affect the circuit. Even if the higher wattage bulbs had fried the wiring, this should not affect the high beam indicator. The higher wattage bulbs could not have fried the BCM circuitry, since there is no direct link between the BCM and the bulbs, due to the circuits being controlled via two relays.

Do you have any other strange things happenings, other than in the IP? If so, it could be the BCM, if not, it probably is the IP cluster.

[Surfcityred]

Thanks for your reply. To answer your questions I'll start with the "before" situation. All was working fine before I went to the higher wattage bulbs.

The only other thing I notice is that the fog lamps will only come on when the high beam indicator is off (and my lights are actually in high-beam mode). Silly, isn't it?

I guess it must be some glitch in the BCM module that was triggered by the higher wattage of the new bulbs. When I take it back for service, I'll re-install the factory bulbs and let them sort it out. Too bad, because the factory bulbs really suck. I can't believe that I am the only H3 owner having this problem. But, perhaps I am the only one using the high-wattage bulbs.

[f5fstop]

Originally Posted by f5fstop

Only thing I can see that could possibly cause this problem would be the BCM or the IPC. Even if the switch was bad, I can't see how this would affect the circuit. Even if the higher wattage bulbs had fried the wiring, this should not affect the high beam indicator. The higher wattage bulbs could not have fried the BCM circuitry, since there is no direct link between the BCM and the bulbs, due to the circuits being controlled via two relays.
Do you have any other strange things happenings, other than in the IP? If so, it could be the BCM, if not, it probably is the IP cluster.

The fogs are also controlled by the BCM via the FOGLP relay, so from troubleshooting it from a few hundred miles away in my arm chair, I would say it was the BCM, but not due to higher wattage bulbs. Like I said, even if you installed bulbs that fried the wiring, it would burn to the relay, and not to the BCM. The BCM does not sense the voltage drop to the bulbs.

Personally, if it were here in my driveway, I would reload the latest calibration into the BCM, just to reset it (reboot it like the computer it is), and see if that cures the problem. Sometimes (and I mean sometimes), this reset works. If that didn't work, I would do some diagnosis, but from looking at the wiring diagrams, the only thing I can see that would be bad is the BCM. Possibly, it could be the IPC, but that does not actually make sense now that you state the fogs come on with high beams. If the fogs came on with low beams, and the blue indicator said high beams, I would say it was the IPC. But you're saying the BCM is turning on the fogs with the high beams, so that makes me say the BCM is messed up.

Not unusual for a BCM just to go, not common, but not unusual.

It won't hurt to replace with stock bulbs, some dealers might say or do something that makes no sense. So play it safe.

[Surfcityred]

Thanks so much f5fstop. I guess I'll swap the bulbs out before I bring it in for my next service and let the dealer figure it out. I think you are right though, since there is zero evidence of any burned wiring or overload of any kind. It must be a BCM glitch. Have a Merry Christmas and a Happy New Year.

[f5fstop]

If you the problem was only with the new bulbs, I could theorize that the new bulbs were wired incorrectly internally. But, the old bulbs caused the same problem.
Good luck....