Installing standalone. What does this black plug go to? Heavy gauge black wire. It's below the brake booster next to main plug. It been awhile since I ripped everything out. 79 Rx7.

 

Just looked at my 1979 GS. I don't have that plug. I do not have AC just for reference.

 

Looks like the hot start assist connector. SA's Should have 2 wires, a solid black and a green / red stripe. The wires for an FB may be different. I know the connection at the assist motor is different btw SA's and FB's

 

Looking further, this is not the hot start assist wire. It comes off the main harness and looks like it runs across the top of the steering box to the top of the engine-under the rats nest and past the alternator. It seems to have a couple possible configurations, depending on when the car was built.

Here is a pic from a March 79 built car and you can see the connector, it usually is under the large triangular shaped boot.



Here are the same wires under the same boot from a Sept 78 built car. The connector seems larger, with an additional white w/black stripe wire off to the side. I suspect this is how KC's car is configured.

 

[QUOTE=Banzai;12654836]Looking further, this is not the hot start assist wire. It comes off the main harness and looks like it runs across the top of the steering box to the top of the engine-under the rats nest and past the alternator. It seems to have a couple possible configurations, depending on when the car was built.

Here is a pic from a March 79 built car and you can see the connector, it usually is under the large triangular shaped boot.



That definitely the same as my car. Next too the big main plug under that rubber boot. I think it goes to the alternator. Thats where I was going to hook it up too. But I wasn't sure. I had all this running before with the standalone. But had to go back to stock for smog to get it registered. There's a similar plug and wire under the steering column. Think it's the main power going to the column. This is a California car with a March 79 manufacturer date also.

 

It's battery positive to the back of the alternator.