Ok.. I'll keep it short and simple (I hope). My car originally had a 5 speed in it, someone decided to swap an th700r4 into it. They did this without wiring up the Torque Coverter, but I wired something up and made it work... The question is, I found a plug under my dash, with the wires that my book says is for the TCC Brake Cancle switch, did Manual and Automatics have the same wiring harness, just with the un-needed parts removed? Is the harness for the TCC controls somewhere tucked away, from when this car was an automatic, or are the wires not there? Can I add these wires from the ECM, through whatever (Brake cancle switch,etc.) and get a PROM for an Automatic car and have it work the way it should? I know someone wired up the Neutral safety switch, because my car will only start in P or N, and the backup lights work. So... basically are the wires there and I just need to find them, or do I have to wire it to the ECM and Brake Cancle Switch? I don't get why the connector for the Brake Cancle Switch is there... Well that turned out longer than I thought... But Please help me. Thanks! p.s. I'll probably post in electrical/wiring too.

I know in my car when I briefly had a manual, I found a couple wiring harnesses that were in the car for manual even thought the car came with an auto. One being the clutch/neutral safety wires. They were just tucked up there where the clutch pedal would be.

I assume the ones for at least the brake switch would be there in your car. Take a peak and see if you can find anything.

Hello TheMysticWizard,
Is that a connector with a thick purple and yellow wire in it? If so, there is another thread on the board from another member who found a connector like this. Check out this link.

http://www.thirdgen.org/techbb2/show...3&goto=newpost

The connector I found has the same color wires as the Brake Cancle Switch should have, One Purple wire, and one Pink/Black Wire. It is also right next to the brake pedal. I am wondering... if I look around will I find the rest of the wiring (the 4 prong connector that goes to the TCC)

If I don't find the connector, Can I just wire these things from the ECM to the TCC, and get a automatic chip? I mean the ECM should be the same for both auto and manual right? Just the PROM being different.

Now that you say it, I also remember seeing the purple/yellow connector under there, but it is connected to a switch which is mounted near where the clutch pedal would be. I also read that some cars have a harness for the Neutral safty switch on the shifter, even though they were originally manual... I hope mine was like that, because I don't like the idea of someone splicing a bunch of wires.

Hey Mystic,

I have a schematic for the TCC from an 89 camaro that I will post on here for you. The pink/black & purple wire you have found go to the Brake Switch. The pink/black wire runs to the gage fuse in the fuse panel and the purple wire goes to pin "A" of the four prong connector for the TCC solenoid. Pin "B" of that connector is a dark green wire and goes to pin "C8" of the ECM. Pin "D" of that connector is a tan/black wire and goes to pin "F" of the ALDL and splits off and goes to pin "A7" of the ECM. Hope this helps you out some

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Wow, I was gonna ask if anyone had those schematics... But I now have a new question, there's 4 ping to the tranny, you told me where 3 of them go, but where does pin "c" go? Is that supposed to be a ground or what? Anyone know?

Thanks Trickster, you've helped a lot.

There is one "empty" connector hole (i.e., no pin and no connection) on the plug that goes into the 700R4 transmission case.

Have fun with your conversion! (I may be doing the same thing in the future)


- Vern

You're welcome Wizard,
As vernw has said, there is one empty slot on th connector. When I was posting, I didn't mention pin "C" because I figured that the schematic showed the wiring connections very well.

Ok, DUH I remember seeing that when I had the pan off my tranny, only 3 wires in there.

I guess I'll just have to wire the stuff up and see what happens with the Auto Chip... will it hurt anything if I wire it up with an Manual chip, I mean I know it won't control it, but will anything be harmed?

I'm not that familiar with that area, you could probably post that on the DIY Prom forum and get Grumpty or one of the others that burn their own chips to give you a good answer to that. I don't think it would hurt anything, but I don't think it would be a good idea to drive it anywhere like that.

As long as you are putting in a 700R4 and not the electronic transmission (4L60E), the ONLY thing the electrical connections going into the transmission control is the torque converter lockup, which usually is set only to occur over a certain speed in 4th gear (overdrive). However, some GM setups will actually do a TC lockup also in 3rd gear.

The shifting of the transmission, both upwards and down shifts, is strictly controlled by the throttle valve cable attached to your throttle body (in addition to the actual throttle cable). Do NOT drive the car without connecting and adjusting the throttle valve cable!!!! You can do a search on adjusting the TV cable.

You can actually drive the car the electrical connection even being hooked up and it won't hurt a thing. It just won't lock up the torque converter and you won't get the best mileage possible in 4th gear. But it will still shift into 4th gear and drive just just fine.

Hope this helps a little bit. Have a Great Day!!!


- Vern

I wrote an article a few months ago about doing this swap an having it work like factory. It is in the TBI section. I wouldn't use a manual prom with an auto. I believe the timing in the chip is different, and the circuit that controls the shift light in the manual controls the TCC on the auto so if you wired everything up to the Manual ECM, it wouldn't engage the TCC right. Also don't forget the 4th gear input to the ecm. I had to pin the ECM connector since it was a manual car and there was no pin for that circuit. I believe it was pin C7.

http://www.thirdgen.org/techbb2/show...hlight=factory

There are actually two wires that go to the ECM. A dark green one that goes to pin C8 and a tan/black one that goes to pin A7. You will see them in the schematic in my earlier post.

I was dealing with a TBI car, I guess the TPI one if different.

You are correct GASGZLR,

On the TBI, the dark green wire would go to pin C7 and the tan/black wire would go to pin A7. I guess GM didn't want to make things easy for us po' folks.

Thanks for the help guys, I think all my questions are answered. I have the thing wired up with a toggle switch right now, if I flip the switch up, it will lock in 4th gear, as long as I'm not touching the brake, if I flip the switch down it will lock up in any gear as long as I'm not on the brake. The middle position is off, no lockup any time.

I plan on wiring it up like it should have been from the factory for an automatic, but I will need a chip for an Automatic.. I have been looking into burning chips, but I don't have the equipment or adapter for my ECM yet. A friend and I are probably going to be playing with PROM Burning this summer, so Hopefully I can burn me a chip then and wire everything up.

I'd just really like to be able to have the lockup work automatically when it should, so I can get some better gas mileage and maybe save my tranny.