Ok, got a 1987 IROC 5.7L Auto that used to be a 305TPI manual. Since I didn't swap the under dash wire harness, I need to cut and splice certain wires to make things work. I just need some confirmation on a few things. I've studied a few wiring schematics and had some questions answered, but a few things still elude me.

On the picture below (which I borrowed from another thread) we have the Auto trans pigtail. Here's what I know about each wire.
A= don't know (caught a rumor it might be a ground?)
B= to ECM (Pin N on C207, idle control)
C= power in from 20 Amp fuse
D= power out (from C) for backup lights
E= dont know
F= dont know




Ok, so at the moment, the only wire I have connected and spliced in is B to the ECM at the C207 connector. Was wondering if A is a ground, and would need to be connected to ground in order for B to work right? Or does B work ok just the way it is?

C and D i want to hookup, but not sure where to splice D into. Any help here would be appreciated, as in what color wire to find and where it is located?

I've heard E and F are for neutral safety, I can currently start the car in any gear, and that doesn't bother me too much at the moment. But where to splice these wire into would be helpfull. Does not having these wires connected anywhere cause any other issues?

Thanks!

 

The 2 thick wires are for the NSS
If the car was a stick then you need to extend the same wires from the clutch safety switch on the clutch pedal to the auto shifter

Blue and green are backup lights
Need to pull up through the floor the two backup light wires ( same colors ) that went to the backup switch on the trans ,and extend it to the shifter

Both go to switches; order not important


Org / blk are for P/N indication to the ECM (blk to ground )
If not hooked up , idle may be unstable when in gear because the ECM has no way of knowing so it can adjust the idle revs accordingly

 

Ok, so I can just run the black wire (wire A) to a ground then? Thanks for the response!

 

Look at a T700 wiring diagram
The org wire from the ECM is switched to ground when the trans is in P or N

 

That is a better diagram than a few I have looked at.

On a separate note.....I swapped in the TC brake switch last night, supplied a 10amp feed, then ran a jumper wire between the purple wire on the brake switch and the purple wire going into the TC clutch solenoid. I tested the brake switch first with a test light with the key on to run and activating the brake pedal, everything seemed to work fine......but when I took the car for a good drive today, it did not seem to lock up. I could not see a drop in RPM at highway cruising speed on the tach either, or a rise in RPM with a tap of the brake pedal. The RPMS are staying the same they were before I put the brake switch in. So I am wondering if there is something else I am overlooking. I swapped the underhood wire harness and ECM when I did the engine/tranny swap, so I believe all the appropriate wires are connected where they need to go...... but like I said, maybe I overlooked something still???