Auto to Manual Swap Help!

I think you need to make a connection where the auto harness used to be, the range selector on the auto has the neutral safety switch in it IIRC

-Michael

Funny you say that. We put the auto trans in nuetral then took the range selector off and plugged in the auto harness and the truck started. But the clutch had to pressed in for it to start?

wint said:

I have the auto PCM, i was told it would work. Harness has been changed. There was a empty plug left over after the auto harness what taken out. Neutral safety switch is brand new and hooked up with a brand new bushing installed. I have tried firing with the clutch in chip installed, clutch in chip uninstalled, factory clutch sensor plug plugged in and out.

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I think you need a jumper at the harness plug that is now empty at the transmission. The wire colors I had mentioned look like the right ones from my read of the diagram. I am having a hard time getting the right read on what you posted. I assume this is a problem with getting the starter to engage.

Got the truck running by using the auto harness and range selector. And yes my problem was getting the truck to crank. I double checked that jumping the solenoid would turn the started and it did. I want to try a manual PCM and see what that does since im told it should work.

So Wint I just switched my sig to ZF-5 a month ago. Just so I'm clear you found the neutral safety switch plug up under the dash it's above and just right of fuel peddle assembly and is attached to the back of the dash adjacent to the firewall. When I switched mine I used the loaner manual PCM and TW chip too (for manual) not problems and fired right up. The tranny wiring harnesses switch right over to unused plugs on the driver's fender liner just below the master cylinder. For me it was plug and play....mind you I have a full parts loaner so it was straight forward swapping for the most part...

I swapped out steering columns as I wanted all the auto sheeit out....let us know how you make out if I can help give a shout...

jrc

There was a unused plug that the manual harness went into? I just unplugged the auto harness and used that. I didn't see any extra plugs while I was there

So for the tranny harness plugs they are located in front and under (on drivers fender liner) brake master cylinder assembly. iirc the plug on the passenger side (roundish one) is used with the Auto harness. One on the drivers side square on is used for both harnesses. I don't know but thinking out loud here if you used auto harness and auto PCM, I would be thinking PCM would be looking to see trucks in park or neutral before allowing to start.

What would happen (as a test) if you unplugged tranny harness at forenoted location (round plug) and made sure the neutral safety switch was hooked up on clutch rod and tried to fire up? Although not totally sure what the round plug circuit is for....


Posted up some pix in the sig link below under Red Truck Folder page 5

So Wint I screwed up the Auto plug and Manual plug on the fender liner are the same plug (square one) and respective harness plugs into that single plug. There is a round plug as noted above that is part of the Auto harness that is not used on the manual set up....sorry for the confusion.....

jrc

Good news. Truck was able to drive home under its own power from the shop that the work was done in.

But im still using the auto harness and auto range sensor. So to solve this problem im going to try a manual PCM and see what happens.

That is a good idea wint glad you got her going.

wint said:

Good news. Truck was able to drive home under its own power from the shop that the work was done in.

But im still using the auto harness and auto range sensor. So to solve this problem im going to try a manual PCM and see what happens.

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I do not think that is the fix by my read of the diagrams but worth a try.

Tom S said:

I do not think that is the fix by my read of the diagrams but worth a try.

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What have you read? That would work?

What I am saying is the starter circuit is not contolled by the PCM by what I see. I can scan some info in from the book when I go back to work next week.

Tom S said:

What I am saying is the starter circuit is not contolled by the PCM by what I see. I can scan some info in from the book when I go back to work next week.

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Alright sounds good. Thanks for all your help!

I quick test would be to disconnect the 104 pin connector from the PCM and try it to see if it cranks.

Tom S said:

What I am saying is the starter circuit is not contolled by the PCM by what I see. I can scan some info in from the book when I go back to work next week.

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This is correct. The PCM doesn't have anything to do with actually controlling the starter. Basically the clutch pedal switch and the auto range selector switch are on the same wire and both have to be "closed" for the starter solenoid to be energized. One or the other is automatically "closed from the factory with a dummy plug that completes the circuit.

I thought I had a wiring diagram of the starter circuit I could post to show this but I can't seem to find it at the moment

-Michael