Ignition switch wiring

[Aaron88]

I got a 1988 3/4 ton I’m rebuilding with a 355. I’m getting to the point everything is ready to run.I’m not the best at wiring so maybe it’s just me. But I was Wiring in the starter but having some issues with it. Got power running to the starter for testing purposes. According to wiring diagrams the larger yellow or purple wire is your starter wire. I get nothing when I got it set up. Any ideas?

 

[Schurkey]

I got a 1988 3/4 ton I’m rebuilding with a 355. I’m getting to the point everything is ready to run.I’m not the best at wiring so maybe it’s just me. But I was Wiring in the starter but having some issues with it. Got power running to the starter for testing purposes. According to wiring diagrams the larger yellow or purple wire is your starter wire. I get nothing when I got it set up. Any ideas?

There's MULTIPLE wires connected to the starter solenoid.

The purple (sometimes fades to pink) wire goes on the "S" terminal of the solenoid. Some solenoids have an "R" terminal, that would not be used on your vehicle. It's REALLY common for that purple wire to be corroded to death inside the insulation. Verify voltage at the "S" terminal when the key is turned to "crank".

Of course, the bigass battery cable goes to the heavy lug. Some vehicles also draw power from that lug via a more-moderately sized cable on the same stud.

 

[Jay88c15]

There's MULTIPLE wires connected to the starter solenoid.

The purple (sometimes fades to pink) wire goes on the "S" terminal of the solenoid. Some solenoids have an "R" terminal, that would not be used on your vehicle. It's REALLY common for that purple wire to be corroded to death inside the insulation. Verify voltage at the "S" terminal when the key is turned to "crank".

Of course, the bigass battery cable goes to the heavy lug. Some vehicles also draw power from that lug via a more-moderately sized cable on the same stud.

I have a similar issue, you're saying that that wire usually corroded under the insulation. Does that wire trace all the way back to the firewall or would I be lucky enough to cut it and splice it? I've been trying to figure out what is creating my no crank issue. Once the key is turned to the on position right before cranking, should I have 12v right at the S terminal? I'll go check right now. I can jump the starter so I'm sure everything else works. I have a new ignition switch as well

 

[Schurkey]

you're saying that that wire usually corroded under the insulation.

Common problem.

Does that wire trace all the way back to the firewall or would I be lucky enough to cut it and splice it?

Goes back to the firewall on older trucks. Newer trucks it goes to the underhood fuse/relay center.

I cut and spliced.

Once the key is turned to the on position right before cranking, should I have 12v right at the S terminal?

No. If you did, the starter would be engaged whenever the engine is running. There's only power to the S terminal when the key is turned past "Run" to "Crank".

 

[Aaron88]

Goes back to the firewall on older trucks. Newer trucks it goes to the underhood fuse/relay center.

Mine appears to be going back into the firewall in the driver side. There is plugs within the firewall for a few different wire harnesses. I unbolted and unplugged them and appears to have some old nasty dielectric grease on them. Could be an issue

 

[GoToGuy]

The grease is doing it's job. It's keeping all the nastiness out. Its not supposed to be pretty, it about function. How do know it's the problem did you ohm check? Continuity check? Test light or multimeter?
Don't guess. Follow the wire diagrams. The wire routing is in the service manual. It's designed and written to work what your problem is not checking things that are not related and wasting your time.
If you check the service manual the wiring schematic, diagrams tell you show you from one point to the next. It's a road map if you use it, it will save you time, time that isn't wasted doing wags.