Random battery, abs, air bag and brake light.

[Slowrc]

I am having this condition happen on my 2000 GMC truck. Just looking for pointers on narrowing this down. I have checked the grounds and swapped alternators. I realize it could be a power feed , ground, ignition switch, or even a PCM issue. Any help is appreciated.

[Taz]

This is a common complaint ... an internet search will lead to hours of reading.

Check and clean:


battery cables
alternator cables
all ground wires


After this confirm appropriate alternator function / output.

If all these check out, it could be the IPC (gage cluster). Sometimes replacing the IPC is the cure, other times this issue continues even with a new IPC.

Electrical issues (which this appears to be) can be a real pain to diagnose / track down.

Time and persistence are your best tools for this .........