Folks, I am a complete newbie to the LS/Vortec swap, so bear with me. I’ve done some EFI/TBI stuff in the past with a 200-4R, so I’m not at a total loss.

What I need to know is the connections for this plug on the 4L60E PNSS. I know there is a connection to my brake light switch, and the starter. The connector is GM part number 88987855 and of course the aftermarket pigtail has no colors or PIN numbers for the six wires. The two at either end are larger gauge than the four in the middle.

The transmission is a 2005 4L60E built for a 4wd Tahoe. The drivetrain is swapped into my 1957 Chevrolet 3200 pickup. I’m using a 1990 S-10 steering column and aftermarket gauges, so I’m not worried about gear indicator interference. I just need the starter and the torque to lock/unlock when appropriate.

Any help will be greatly appreciated.

-Joe

 

Okay, just a bit more info. The two larger outer wires are for the starter in Park and Neutral. I was able to confirm this with the pigtail installed on my transmission while testing continuity in each gear, with each wire. In Park and Neutral, the pair are linked, so they would be the starting circuit. Now I just need to know about the brake light switch interface for the torque converter to unlock/lock.

-Joe

 

For the record, you don't need that connector to run/ start the engine. I didn't use it on the last swap I did.

 

Thank you very much! Mystery solved. I appreciate the help!

Have a Merry Christmas!

-Joe

 

So I’m I correct in that I’m overthinking this side of the transmission. The PNSS isn’t an issue unless I want to ensure it doesn’t start in gear?

All of the transmission controls, (torque converter lockup/unlock are on the right (passenger side) through the round connector, and are managed by the PCM, correct?

-Joe

 

The PNSS will also send signal to PCM as to what gear is selected. The PCM will use this signal to increase the idle speed when shifting from Park/Neutral into Reverse/Drive. Is this needed to run, no but could help with stalling if using a large camshaft when shifting into gear.

For safety reasons I highly recommend that the park/neutral switch be hooked up. You may be able to remember that it will start in gear, but anyone else helping to work on or operating the vehicle may not. It's not that hard to wire up.

 

Huh, I did not know that, but it makes sense.

The latest build I did had an issue stalling when shifting to reverse. If I remember correctly, the version of 4L60 he was using (pre-'99) wouldn't accept a PRN switch.

One thing I forgot about is that the PCM requires an input from this switch if you want to do a cam/ crank relearn. There are ways around it, but it would be easier if it is in place.