[sglemans]

On my 72 Lemans, there is a large rectangle connector that's partially disconnected that comes after the ac resistor, since my AC is off the car I am wondering where it is supposed to go. Also a smaller one with 3 prongs, as in the attached pic's. Any ideas?

[428GTO70]

I believe the first one is the ac extension harness. One of the wires goes to the back of the alternator which feeds full power to the blower motor for high speed, and the other wire goes to the AC compressor clutch. You would want to keep the power feed to run the blower on high for your heater, if you are still using it that is. Not completely sure on the 3 prong one.

[sglemans]

OK, thank you. I wonder what the need for this connector is in the first place?? Doesn't seem to exist on the pre-1972 models.

I believe that the power wire is cut on the other side near the brake booster. Nothing attached to the alt. right now. Is this necessary for just the high blower, or are all the 3 other fan speeds independent of this setup? Right now I have no power to the blower, as in the other post.

Also, which replacement wire harness comes with this connector, as well as the AC relay connector? Is it the main eng. harness or the AC harness?

[428GTO70]

well, actually I do have that connector on my 70 GTO. It only feeds the high speed on the blower and goes into a relay on the firewall. I don't have that wire hooked up right now and I have no high speed at the moment but I do have the other speeds.

[sglemans]

428GTO70, which wire is that that is not hooked up? Trying to figure out which wire goes where on the relay.

Does anyone have a pic of the relay with the wires hooked up that shows the wire colors?

[428GTO70]

I've only been going off memory so far on this. I will have to go take a look when I get a chance to confirm stuff. I also have a wiring diagram for 72 Lemans somewhere I can check as well.

[Ben M.]

The 3 prong connector is your temperature sender idiot light and TCS temperature control all-in-one switch that goes in the passenger side head. 1972 only in that location, 1970-1971 were on the intake.

[sglemans]

Can I plug in the 3-prong just to use for the temp sender light without hooking up the TCS? I currently have an aftermarket temp guage plugged into the drivers side head area, but I would like to have the temp light as well. No TCS anywhere on the car. Would this cause any issues?

What about doing the same thing for the oil pressure light? Is that sender a dk greenish connector with a little round rubber "umbrella" around it?

Also, I don't see the lights come on when starting, is that because the senders are off or some other reason? I only get the alt. light when turning to start/run.