Help with wiring!

[Cu1n81]

Guys, in my attempt to clean up the rats nest under my hood near my fuse box, I try to remove any unnecessary wires. Now my truck won't turn off with the lights on? What in the world could cause that?

 

[squaredeal91]

Do you still have what you removed? What year and engine size?

 

[jallen]

1980 small block 350. I have the stuff but I can’t remember what goes where. I’ve tried about every combination I can. Did I cut a ground by accident maybe?

 

[squaredeal91]

Cutting a ground can cause weird things to happen. it could Make things hunt. I'd start with ground checking. Maybe someone will chime in w/ all the underwood grounds

 

[jallen]

Connected all ground wires. My gauges work but my truck will not turn off if I switch it off with my headlights on. Help!

 

[squaredeal91]

I got nothing to bring to this table.
@Ricko1966 any idea's
anyone know wiring?
Maybe @Grit dog
join the party lol

 

[SquareRoot]

Perfect time for the venable LS Swap

 

[kzguns]

sounds like the hgeadlight ciurcut is back feeding the ignition. I'd start by tracing that all the way back.

 

[Grit dog]

Connected all ground wires. My gauges work but my truck will not turn off if I switch it off with my headlights on. Help!

Maybe unplug the headlight switch and see if that fixes the issue?

 

[Radiohead]

Just don't shut it off at night. Easy

 

[Gilmore]

I'd vote for KZGuns' path to this issue and get up under there and look at all of the ignition wiring and see if they have back fed something off the hot or grounds from the headlight wiring.

 

[rich weyand]

Is the ground from the rear of the passenger-side valve cover to the firewall in place? If that is missing, the cab will be floating, and all kinds of crazy stuff will happen.

 

[Grit dog]

1980 small block 350. I have the stuff but I can’t remember what goes where. I’ve tried about every combination I can. Did I cut a ground by accident maybe?

Like @rich weyand said, Yes a bad or missing ground can and does sometime cause otherwise inexplicable electrical issues.
Obviously inspect and clean all grounds. But if you don’t have confirmation of good ground chassis to engine, engine to cab, chassis to cab and chassis to bed don’t waste a bunch of time. Easy to temp wire up real quick a set of new grounds and 1 at a time see if each solves the issue.
Because my previous suggestion of confirming it’s not the headlight switch “shouldn’t “ be a cause for ignition issues anyway as there are no circuits through the headlight switch that are ignition controlled.

 

[wlwarnke]

I don’t see a missing ground preventing the engine from shutting down. Plus there aren’t any grounds coming through the bulkhead.

Truck will start fine, but can’t shut off the engine, if the headlights are on?

HEI distributor? Single wire from bulkhead to distributor, usually pink and fairly heavy gauge.

Looking at the bulkhead, unbolted, it’s actually 3 pieces. Main piece is engine/power wires. Middle is front lights, rear is tail lights.

Usually 2 big red wires from firewall, or starter, or battery feed the truck. Big pink is ignition feed, big purple is crank to starter. 2 smaller wires, can’t recall color go to alternator to turn it in, maybe brown?

 

[Terry Wilkerson]

Just moving wires around during your wire cleanup may have caused the problem. If the power headlight wire is bare and making contact with ignition wire possibly rubed through would cause exactly what your saying. If someone knows where the ignition and headlight wires run close together that might be a good place to look.
Always unhook the battery each time you work on electrical. Easy to rehook it to see if you have found the problem.