Electrical issue

[henderson7.3]

New to forum so any feedback is appreciated.The problem doesn't happen often but when I start the truck, the abs lite will stay on, the a/c doesn't work,nor do the blinkers and the speedometer.I do have tail and brake lights and the tachometer works which seems weird to me.Its a 2000 7.3.The guy I bought it from said it may have something to do with the Jake brake that was installed.The problem does not seem to affect the performance and the problem goes away like magic while driving.I know this because the abs light on the dash will go off and everything starts working again.Help...........Please.

[Turbostang500]

Sounds like a bad connection somewhere.

Maybe the gem module or body module?

[TheFordman87]

Rule of thumb any electrical problem start with looking at anything aftermarket installed on the truck

[henderson7.3]

Thanks for the replies,now I have a place to start.

[HillClimber350]

Sounds like possibly a connector on the firewall

[jc82chevyman]

The best place to start would be with wiring diagrams and locate the circuits that are malfunctioning the isolate those circuits to determine if the other symptoms are located in the same connector or controlled by the same module