I have a couple of questions.
Is the momentary crank position where you turn the key to the position right before you start it?
And should I let the car run to let the battery charge? I ran it for a bit and it's now at 14.3x volts.

 

The crank position is the last clockwise position which is momentary and when the starter is supposed to engage. You can charge the battery with the engine or a battery charger.


George

 

Gotcha.
The LP PARK under the hood reads 0.014 volts.

 

Both sides of the fuse (still installed) or the socket contacts (fuse removed)?

 

Still installed with the LP PARK.
Removed with the CRANK which was 12.01 volts.

 

So there is no voltage at the Park LP fuse in the UHFB but the truck starts? If that's correct then there is a problem with the wiring right at the UHFB because the same always on battery feed goes to the Ign C fuse (UHFB) that is needed for cranking and the Park LP fuse (UHFB). If this is correct then in addition to no IPC illum lights you will have no parking or head lights, the dash headlight sw and illumination thumbwheel will be completely dead. If this is correct then there may nothing wrong with the ignition switch. This can be confirmed with a FUSED jumper wire to temporarily bring power to the Park LP circuit. It must be fused.

You get 12v at the crank fuse with the ignition switch in the crank position when the truck will not crank, is that correct? Again, then there may be nothing wrong with the ignition switch and these are two completely separate problems. Your problem would then be down stream of the crank fuse and we move on to measurements at the starter relay. When the truck will not crank try wiggling the gear selector while in park and again in neutral to see if that helps. Then it would be the position switch on the trans.

George

 

I have parking and headlights.


Also the truck won't crank when i get the 12 volts, without the fuse.


Another also, the car has been starting fine while doing these tests. If you want i can send some pictures.

 

Big Woops! I confused PARKLP fuse with LR PRK. I'm getting a reading on the actual parklp fuse. 12.58 volts.

Sorry about that.

 

Forget what I said about the headlights, that's separate circuit, sorry about that.

When you don't have any IPC lights what about the other illumination lamps on that circuit: headlight switch, fog lamp, rear wiper, HVAC module (HL switch in manual on mode)?

The crank fuse is in the start path. The point of testing it is that we need to find the failure when you are stranded with a no crank situation. Then you test for 12v arriving at that fuse when the ignition is in the momentary crank position. We know that you will always see 12v under normal starting conditions in crank mode.


George

 

Nothing on all of the lamps you mentioned.