
BEWARE! A/M LED headlights can upset BCM and busses
Saw this first last year in a 19 Impala, thought it was a
fluke and a one off. IP would cut out with several warning
lights, many U codes. Could see on scope both high speed CAN
and low speed GM LAN going whacky. It was intermittent and
made no sense whatsoever. Decided to replace the BCM since
the only place busses come together. Did not help, I was
stumped. Finally discovered thet the LED conversion
headlight bulbs, more specifically the little fans were
causing the problem. Auto headlights were on inside shop.
Turn the lights off, perfect data signals, turn them on and
goes crazy again. I still don't know how it can backfeed the
BCM driver circuits. On the Impala either light plugged in
alone would cause the problem. Also the fans on the "bulbs"
were noisy. I scoped the driver circuits and couldn't see
anything, so I'm assuming must be RFI from the little fan
motors somehow interfering with BCM. These bulbs were
installed 6 months prior with no trouble until there was.
Kevin Baker ![]()
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Engine | 5.3 L |
Trans | 6-speed Automatic (Electronic) |
Vehicle Data
2015 Chevrolet Silverado 1500 LT 5.3L
Engine | 5.3 L |
Trans | 6-speed Automatic (Electronic) |