2 harnesses?

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2 harnesses?

Postby 77nighthawk » Fri Nov 20, 2015 11:08 pm

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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If it don't scare me, I don't want it.

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Re: 2 harnesses?

Postby SeniorSavage » Sat Nov 21, 2015 12:35 am

hope this helps
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The fleet;
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Re: 2 harnesses?

Postby SeniorSavage » Sat Nov 21, 2015 12:57 am

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
The fleet;
1975 Buick Skyhawk 3.8 V6 turbo - total restore ongoing (soon!)
1980 Buick Riviera 5.7 Olds 350 Rocket - restored daily driver
1984 GMC G30 5.7 350 Chevy sbc 20' Okanagan motorhome - for tight spots
1996 Fleetwood Bounder 35' Ford 460 TBI motorhome - for not-so-tight spots
2004 Harley-Davidson Heritage Classic 88ci 1450cc. - custom original.
2007 Ford Escape XLT 3.0 V6 AWD (wifes truck) - working original.
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Re: 2 harnesses?

Postby 77nighthawk » Sat Nov 21, 2015 1:20 pm

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
If it don't scare me, I don't want it.

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Re: 2 harnesses?

Postby 77nighthawk » Sat Nov 21, 2015 2:11 pm

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.

20151121_114141r25.jpg
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I'm guessing the v6 harness I have is for a non-ac car?
If it don't scare me, I don't want it.

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Re: 2 harnesses?

Postby spencerforhire » Sat Nov 21, 2015 3:40 pm

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.
The "fleet"-
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Note- the very act of listing all of these has made me realize I have some kind of problem.....

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Re: 2 harnesses?

Postby zeke » Sat Nov 21, 2015 5:01 pm

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.
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Re: 2 harnesses?

Postby 77nighthawk » Sat Nov 21, 2015 5:59 pm

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?
If it don't scare me, I don't want it.

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Re: 2 harnesses?

Postby zeke » Sat Nov 21, 2015 6:17 pm

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.
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Re: 2 harnesses?

Postby 77nighthawk » Sat Nov 21, 2015 8:02 pm

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.
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Re: 2 harnesses?

Postby zeke » Sat Nov 21, 2015 8:18 pm

It's just an ignition source.
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Re: 2 harnesses?

Postby 77nighthawk » Sun Nov 22, 2015 5:42 pm

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
If it don't scare me, I don't want it.

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