painless wiring
 

I have rewired my 72c10 with a painless kit. My problem is when the brake is applied all of the rear lights turn on less the bu lights. Those are wired to the shifter. The after market gauges also light up. No problems in the front. Also the turn signals dont work with the headlights on and all of the rear lights work with the signals. I have ground straps everywhere. All wiring switches bulbs etc are new. Any advice would be greatly appriciated. Thanks

Re: painless wiring
 

Every electrical issue has its own solution, there is no "common" solution to every problem.. Probably 80% of issues such as yours where there are several faults showing up from just one action, such as an additional light coming on when a totally different light is turned on is a problematic ground somewhere..

Your symptoms are classic faulty ground systems and or connections. You mentioned you have ground straps "everywhere".. The most important locations are:

#1 - Negative battery cable attached to engine block..
#2 - Negative battery "pigtail" connected to radiator core support.
#3 - Ground strap connected between engine block and frame.
#4 - Ground strap connected between engine and firewall/cab. This one is typically connected to the rear of the passenger side head and one of the studs that mounts the heater case to the fire wall.
#5 - Ground strap between frame and cab floor braces. One on each side would be better.
#6 - Ground strap between bed and frame..
#7 - coming out of the wiring harness behind the instrument cluster is a black wire with a "pinch style" clip on it.. This is the ground wire for the instrument cluster.. It must be attached firmly to the metal dash.
#8 - Each headlight bulb grounded to radiator core support.
#9 - Tail light housing's and turn signal housing's ground path is through their respective mounting points.. These areas must be clean and free of corrosion, paint, and/or powder coating. If lights are mounted to the bumper, the ground path is light housing, bumper brace, into the frame.. All these mounting points must be clean, free of corrosion, paint and/or powder coating.

ALL ground straps are electrical connections.. The connection points must be clean and free of any corrosion, paint, and powder coating.. Bare metal-to-bare metal contact surfaces..

Re: painless wiring
 

I forgot to mention that the engine and trans aren’t in yet. I would like to solve this lighting problem before in install them. Could this be a problem?

Re: painless wiring
 

Engine and transmission not installed, in and of itself, will not cause those problems.. However missing or disconnected grounds due to the engine being removed will cause them...

Go back and re-read my 1st post.. Go through all 9 points, and establish good grounds.. When doing a re-wire, whether it's a complete or partial, pick one circuit.. Make all the connections for that circuit.. Connect the battery and check that circuit.. When you have that ONE circuit functioning properly, move on to the next circuit.. Do so for each circuit.. If a problem "pops up" at the end of a circuit completion, you will then know the problem is with THAT circuit..

Re: painless wiring
 

Rusty Pile is 100% Correct...90% of electrical problems are grounding issues.