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2 harnesses?

PostPosted: Fri Nov 20, 2015 11:08 pm
by 77nighthawk
Ok, popped the hood on my 79, and found that whosonfirst had started changing the engine harness from a 4 cyl, to a v6 harness.

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I managed to remove all but 1 wire. It is a black wire with red stripe. I don't know what it's plugged into is for. Any ideas? Is this just for 4cyl engines? There is a 2nd box(relay?) mounted on the right inner fender. I'm guessing that one is for ac? Any help is GREATLY appreciated. Brad

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Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 12:35 am
by SeniorSavage
hope this helps

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 12:57 am
by SeniorSavage
hope this helps

send me email and ill send you some more good ones bigger than 256kb

1979_Buick_Skyhawk_Monza_Starfire_and_Sunbird.pdf

1978_Chevrolet_Monza_Sedan_and_Station_Wagon.pdf

1979_Buick_Skyhawk_Monza_Starfire_and_Sunbird.pdf

1980_General Motors_Skyhawk_Monza_Starfire_and_Sunbird.pdf

cheers

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 1:20 pm
by 77nighthawk
Hey SeniorSavage, thanks for the reply. I went through the wiring diagrams in the best of section, and the only wire I found was black with pink stripe. It shows to go to 4cyl throttle/sol or 6cyl carb vent/sol. There are 2 other wires in that connector, on the harness. A black wire and a lt green w/blk stripe wire. The black wire isn't connected to anything, but the lt green w/blk stripe wire goes over to the passenger side harness, plugs into a double pin connector with 2 lt green wires that goes back through the firewall by the blower motor. I'm not seeing any of this in the wiring diagram. Is this harness maybe for a different year Monza? Brad

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 2:11 pm
by 77nighthawk
Ok, I went back out to the garage, and looked over the wiring. It has something to do with the ac. Here's a pic of the connector going through the firewall by the blower motor.

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And here's a pic of the other wire on the engine side of that connector. It's the ac compressor clutch wire.

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I'm guessing the v6 harness I have is for a non-ac car?

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 3:40 pm
by spencerforhire
Unfortunately, none of the Mitchell Vintage diagrams I have posted in the "Best Of" section are for cars with A/C. Ditto for cars with factory gauge cluster with tach.

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 5:01 pm
by zeke
If it were a black/yel I'd say it could be a coolant level sensor wire. Check it for power and if none, try grounding it and see if any lights come on.

Your extra relay could be an anti dieseling relay, part of the compressor clutch control circuit.

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 5:59 pm
by 77nighthawk
Hey Spencerforhire, this one shows components for ac.

download/file.php?id=5152

Chris, the wire is definitely black with a pink or red stripe. I traced the wire back into the firewall harness plug, and on the v6 harness, the wire is solid black. On my Nighthawk, there is no wire in that spot.

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Something just occurred to me. If you change the engine harness, do you need the change the harness behind the firewall as well?

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 6:17 pm
by zeke
They didn't need to change the harness for an engine swap, maybe there were other issues.

My 79 (orig v6) with A/C doesn't have a wire there.

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 8:02 pm
by 77nighthawk
As per the diagram on this link: download/file.php?id=5152

The wire in question is pin 39 of the bulkhead connector, as seen from dash side. On the engine side, it leads to the 4cyl throt/sol, or 6cyl carb vent sol, on the dash side, it changes to pink 25, where it joins with 10 other wires in a junction, 8 of which lead to either a printed circuit board, idiot lights, or gauges. 1 wire leads away, and tees to 2 more wires, 1 goes to seat belt wiring sw & timer, the other goes to an unknown connector pin 39. The last wire of the 11 wire junction, is pink 26, which goes to the fuse box.

Re: 2 harnesses?

PostPosted: Sat Nov 21, 2015 8:18 pm
by zeke
It's just an ignition source.

Re: 2 harnesses?

PostPosted: Sun Nov 22, 2015 5:42 pm
by 77nighthawk
Just an update. I went ahead and removed the wiring in question. I looked in my 78 service manual, and it shows a wide open throttle switch, mounted to the carb, that shuts off the ac, under hard acceleration. I don't think I need that. Brad