Will not start and keeps blowing # 20 (prnd21) fuse when shifting out of park

[William Mosley]

Still have no signs of life, but I not going to give up on her just yet.

 

[SunlitComet]

so this time with the starter relay removed the light still only comes on with it in start and the fuse blew again?

 

[ktmhans]

So what exactly did the mechanic do? Was the truck running well when you dropped it off, except for the problem, is it possinle there was a totally faulty part installed?

 

[William Mosley]

Yes gear indicator only comes on when key is in start mode, not on mode. I will inspect the power block today.

---------- Post added at 07:26 AM ---------- Previous post was at 07:23 AM ----------

I took the truck to the mechanic bc trans went out. I'm using a trans out of a wrecked one. That I was able to drive home. No problems just wrecked.

---------- Post added at 07:27 AM ---------- Previous post was at 07:26 AM ----------

What color wire am I looking for under the power block. Earlier u mentioned that it splits into two leads from the number 20 fuse. What color are those 2 wires?

---------- Post added at 07:28 AM ---------- Previous post was at 07:27 AM ----------

Are these two problems related? Bc they happened at the same time?

---------- Post added at 07:30 AM ---------- Previous post was at 07:28 AM ----------

If i jump a wire from the starter relay to the ignition switch harness will this short something out?

 

[SunlitComet]

Power Distribution Diagrams
Power Distribution

Notes

Power Distribution

Notes

Power Distribution (Cont)

Notes

Power Distribution (A, B & C Cont)

Notes

Power Distribution (F, G, H & J Cont)

---------- Post added at 12:40 PM ---------- Previous post was at 12:29 PM ----------

if it still acted the same with starter relay out then I would suspect the wires going sharing the main bulkhead disconnect could have gone bad somehow.

The tranny fuse is in the cap fuse panel and is pink on output and splits into to two on going thru the bulkhead connector(c100) just like the starter circuit from key to relay on under hood block.

You can try from key to starter relay with no problem. I want to to know the results as well. just not from key to starter solenoid.

Don't know if they are related yet but we will soon find out. I am also wondering if the +voltage from starter circuit leaking into the tranny internal harness to light up gear selection display somehow? That would almost have to be confined to tranny area.

BTW Double check your starter for proper connections.

---------- Post added at 12:42 PM ---------- Previous post was at 12:40 PM ----------

Harness Connector
C100

Notes

C100

---------- Post added at 12:42 PM ---------- Previous post was at 12:42 PM ----------

C100

Notes

C100 (Part 1 Of 2)

Notes

C100 (Part 2 Of 2)

---------- Post added at 12:44 PM ---------- Previous post was at 12:42 PM ----------

Starting and Charging System

Starter And Charging (Part 1 Of 2)

Starter And Charging (Part 2 Of 2)

 

[William Mosley]

I don't know that the old ignition switch is bad or not I just replaced bc it seemed the right thing to do and I had one on hand and the truck was already taken apart

 

[SunlitComet]

Disconnect the batery power and probe the switch wires for proper operation using continuity testing and the switch diagram I posted to be sure if you want.

 

[William Mosley]

Let me clarify this. First issue: The truck will only start if I jump a wire from under the dash, just behind the ignition switch wiring harness. To under the hood to the starter relay. If I don't jump the wire when I try to start it I move the key to the on position everything works as it should the I move it to crank position and nothing happens except the shift indicator lights up until I release the key from the start position back to the on position.

Second issue: when it is either cranked or not if the key is in the on position, when I move the shifter from park to reverse it blows the # 20 fuse. If I put a new fuse in after I have shifted passed reverse the fuse does not blow. even when moving back to park.

Now could this be bad.... the electronic device that's on a rod along the steering column? There is a pigtail with two wires coming off the ignition switch that plugs into it. it moves when the shifter moves. What exactly does this part do.

Could this be something with my back up lights,

It sounds like the truck does not know it's in park. And it don't know that I'm applying the brake when shifting out of park. For some reason I don't have to apply the brake to shift out of park, why is that????? Does anybody know?


Also could this be something bad in the trans. Itself?

 

[SunlitComet]

Brake interlock for transmission that releases when brake is applied to allow shifter out of park. it is actively locking when key is in "RUN' or "START". If unplugging it and moving the rod manually still blows (interlock is fuse by #16-turn back-up btw) I am thinking you may not have any choice but to unwrap your harnesses that go thru the bulkhead connector for inspection for a burned thru wire. All the circuits that could be the issue run thru those harnesses. You have already have narrowed it down to a certain wire bundle. If you separate the bulkhead connector it would be faster to track down what side you need to inspect. I can give you all the diagrams you would need.

 

[William Mosley]

So if I'm able to shift out of park without applying the brake, this means that this part is bad right.? And also yes any diagrams you have would be greatly appreciated.