'72 engine wire harness help

[R N.]

Hello All,

I'm in the middle of replacing the A/C wire harness on a '72 (base engine with A/C and automatic) and I've come accross this wire that was chewed off from a mouse and I don't know where it goes.

It's an orange wire, I'm guessing 14 ga. and it comes out of the engine harness on the firewall at the back of the RH valve cover area. This is the harness that runs down to the starter.

I've tried to follow the electrical drawing in the service manual and I only see an orange wire going to the blower motor, but I assume that because this is an a/c car it is different.

Can someone help please....

[Fred D.]

Re: '72 engine wire harness help

Kurt,

I have the engine and just went out to the garage to look but on that side I don't see an orange wire other than the 10 gauge one coming from the horn relay, going to the AC relay. I don't think that wire is in the AC circuit.

I do see an orange wires coming out of the firewall, going down the left side and back. Looking at my oOSOEZ print, I see a 14 gauge for the stop-lamp switch, blower motor and one for the alarm key switch. Do your brake lights, blower and alarm all work?

[R N.]

Re: '72 engine wire harness help

Fred,

I've run the orange wire already from the A/C harness over to the relay. This wire is coming out at the same point as the blue & tan wires do that go to the TCS solenoid on the intake under the carb on the RH side.

The alarm doesn't work from what I was told as it's a friends car I'm working on.

Kurt,

I have the engine and just went out to the garage to look but on that side I don't see an orange wire other than the 10 gauge one coming from the horn relay, going to the AC relay. I don't think that wire is in the AC circuit.

I do see an orange wires coming out of the firewall, going down the left side and back. Looking at my oOSOEZ print, I see a 14 gauge for the stop-lamp switch, blower motor and one for the alarm key switch. Do your brake lights, blower and alarm all work?

[Fred D.]

Re: '72 engine wire harness help

Kurt,

Could it be for the alarm then (that was my first hunch)?

My print shows an orange 18 gauge wire going to the Auto Trans TCS switch from the the Accel Pedal TCS switch.

Further for the TCS/T400 circuit, it shows a black 18 guage wire coming from the Ignition Harness to firewall connector to the Auto Trans TCS switch. And a tan 18 guage wire going to the Accel Pedal TCS switch from the Ignition Harness to firewall connector.

[R N.]

Re: '72 engine wire harness help

Fred,

Is that the Auto Trans TCS switch mounted down on the transmission?

[Fred D.]

Re: '72 engine wire harness help

Kurt,

Not 100% sure, but would assume so (maybe someone else will know for sure). I will take a look at my car a little better next chance I get (hopefully tomorrow) and see what I can see. If I find anything, I'll let you know...

[R N.]

Re: '72 engine wire harness help

Fred, I may of found the answer. On UPC C60 sheet E1 it shows the orange production wire for the blower leaving the main engine harness along with a black wire for the blower ground. It states to cut orange wire to within .25" of break-out and discard connector.

It's all making more sense now as the black wire that is with the orange wire on this car does connect to the a/c blower ground connector on the a/c harness.

Thank-you for the help.

[Fred D.]

Re: '72 engine wire harness help

Kurt,

That sure sound like a logical reason as to why you have the extra wire (and why I don't). I just got home from church and was heading out to the garage to install my restoration battery & look for orange wires