Wiring harness issues-need help!

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Wiring harness issues-need help!

Postby JimW » Fri Nov 11, 2011 7:47 pm

I need some/alot of help identifying my harness and connections. We have a '77 Astre that we purchased with no engine and trans. We have everything installed except the engine harness and dash wiring. When we bought the car it came with harnesses that appeared to be factory. But after looking at the wiring diagrams that Spencer posted for a 77 Vega, I've discovered that ours is not the same.
Is the Astre wiring different than the Vega? If yes, then does anyone have a wiring schematic? If no, then I guess I'm in need of alot of help.

I checked through all of the diagrams on Spencer's post and none of the bulkhead arrangements match ours. The 1st thing I was checking was the oil pressure sensor as I intend to use an in tank fuel pump and I wanted to use the stock setup. But, when checking the wiring, I found that the three wires that supply the sensor are as follows when looking at the sensor plug from the sensor side : at the 9 o'clock position is the pink wire that runs to the iginition switch, at 12 o'clock is a blue wire that goes to bulkhead connector 'O', and at 3 o'clock is a black wire w/ a white stripe that goes to a seperate plug in the proximity of the bulkhead connector.

For some background, I believe that this harness was used with a V6 that someone installed prior to us purchasing the car. I am in the process of verifyig wiring on the inside bulkhead connector.
I could use a picture of the fuse panel with fuses labelled as ours is not very legible.

Any help is appreciated - thanks
'64 Buick Wildcat w/401 Nailhead in restoration process
'67 Chevy C20 (son's daily driver)w/Inline 250 - lumps, big valves, Offy intake, Holley carb, Langdon Headers, 240 hp w/ T5
'77 Astre SBC 327 with TPI, Megasquirt EMS, 200-4R
JimW
 
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1977 Pontiac Astre Hatchback


Re: Wiring harness issues-need help!

Postby spencerforhire » Fri Nov 11, 2011 9:48 pm

The Astre wiring may be slightly different if the car originally came with the "Iron Duke" 2.5 liter pushrod motor. I think I read somewhere that they had mechanical fuel pumps instead of electric. If someone previously had a V6 in there, they may have used a Monza harness.
I have found some discrepancies in the diagrams I posted out of the Mitchell Vintage program; the Vega ones are for the non GT "sweep" speedo dash instead of the round gauge dash with full instruments.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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1972 Chevrolet Vega Hatchback

Re: Wiring harness issues-need help!

Postby stage169 » Fri Nov 11, 2011 11:31 pm

Jim this might help some its from a 1977 Buick Skyhawk manual and they only came with the V6.

If I remember correctly on mine the oil pressure swicth wire colors are pink (ign) Purple (starter) and Dark Blue (fuel pump).

Brian
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Re: Wiring harness issues-need help!

Postby JimW » Sat Nov 12, 2011 12:35 am

After digging into this further, I do believe that the engine harness is not the original, as the pins on the engine harness bulkhead connector do not match up to the mating bulkhead. The light protion does match up though. We've guessed that this harness functioned and was used becaue there are multiple wires that were lengthened to fit the engine.
Spencer - there is an electric fuel pump in the fuel tank. Also, this has the 'GT' dash panel, but I'm still trying to figure out the dash panel wiring.

Stage 169 - do you have the rest of the diagram in your attachment? If so, then I would really go for it.
'64 Buick Wildcat w/401 Nailhead in restoration process
'67 Chevy C20 (son's daily driver)w/Inline 250 - lumps, big valves, Offy intake, Holley carb, Langdon Headers, 240 hp w/ T5
'77 Astre SBC 327 with TPI, Megasquirt EMS, 200-4R
JimW
 
Posts: 98
Joined: Sun Dec 12, 2010 12:42 am
Location: Upstate NY, Binghamton area

1977 Pontiac Astre Hatchback

Re: Wiring harness issues-need help!

Postby spencerforhire » Sat Nov 12, 2011 8:15 am

The differences between the normal and GT dash wiring are also compounded by the presence of an ammeter on the early GT cluster; the harness for these cars brings the main power wire from the alternator into the dash and back to the battery. The later GT's with a voltmeter have the same underhood harness as the regular sweep dash. It's not in any of my diagrams, but it's a black and black/white pair of 14g. wires that terminate in a tan 2-pin plug behind the cluster.
The "fleet"-
72 Vega HB Drag Car -383/'Glide/9"(9.35@146.19)(5.94@117.28 1/8th)
77 Vega Estate wagon- project(someday)will have TPI305/T-5, S-10 spindles/axles
76 Vega GT- 400/4spd/9" retired from active duty(rusty)
06 Silverado 2WD ex.cab daily
03 Silverado 2WD ex.cab (retired)
06 Haulin' 20ft enclosed car transporter
06 GMC Canyon Shop truck
07 Colorado project( 5.3 4L60e swap)
99 Saturn SL1- wife's car
01 Saturn SC2- son's project
07 Saturn Ion Redline project
and 4 more Saturn "parts cars"
Note- the very act of listing all of these has made me realize I have some kind of problem.....

Visit http://www.spencerforhire.ca
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Location: Halifax, Nova Scotia

1972 Chevrolet Vega Hatchback

Re: Wiring harness issues-need help!

Postby stage169 » Sat Nov 12, 2011 9:36 am

JimW wrote:Stage 169 - do you have the rest of the diagram in your attachment? If so, then I would really go for it.


I only have the Buick info but Spence has fixed everyone up with this post. There are a ton of schematics to look at here viewtopic.php?f=19&t=22240

Brian
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Re: Wiring harness issues-need help!

Postby JimW » Sun Nov 13, 2011 9:23 am

Thanks for the help. After checking out the chassis side of the bulkhead connector I think all is well.
There are two additional wires on the chassis harness that aren't in the engine harness. One is a small (16-18 gauge) brown wire in position 5, and the second is small (16-18 gauge) green wire in position 13.
I labelled the positions as follows :
Engine portion of engine side of bulkhead

Engine portion engine side of bulkhead
#3 Blue to Oil Pressure Sensor(OPS) 12 o’clock
#5 Brown wire not in chassis bulkhead plug
#6 Black w/red stripe (chassis connector pink 16 ga)
#7 Pink OPS 9 o’clock
#8 Purple (cut off and not hooked) believe for OPS
#9 Red w/fusible link at bulkhead to starter (main power)
#10 blue wire for wiper motor connector
#13 Dark Green not in chassis bulkhead plug
#14 Brown wire (to alternator for light I think)
#15 Black wire for blower motor (Orange on chassis side)
#16 Yellow wire for wiper motor
#18 Dark green coolant temp (pretty sure-maybe level )
#20 Black w/white stripe for wiper motor

I numbered the bulkhead locations from looking at the connector as in wiring diagram. #1 is at the top left and #20 is at the bottom right. The numbers that are omitted do not have wire pins in those locations. I tried to attach a pic/MSWord unsuccesfully :( . (Why did GM use the crazy letter system?)

As mentioned previously, there is a large gauge black wire w/white stripe hooked to OPS at 3 o'clock position that doesn't connect in bulkhead but has a factory looking connector that terminates near the bulkhead connector. Also, there is a spliced in pink wire, large gauge, into pink OPS wire, I'm quite sure that this is the for the ignition.

Questions,
Should I be able to connect the cut purple wire to the OPS and remove the black w/white stripe wire?
Are the pink and blue wires connected properly at the OPS?

Thanks again
'64 Buick Wildcat w/401 Nailhead in restoration process
'67 Chevy C20 (son's daily driver)w/Inline 250 - lumps, big valves, Offy intake, Holley carb, Langdon Headers, 240 hp w/ T5
'77 Astre SBC 327 with TPI, Megasquirt EMS, 200-4R
JimW
 
Posts: 98
Joined: Sun Dec 12, 2010 12:42 am
Location: Upstate NY, Binghamton area

1977 Pontiac Astre Hatchback

Re: Wiring harness issues-need help!

Postby stage169 » Sun Nov 13, 2011 6:36 pm

JimW wrote:Questions,
Should I be able to connect the cut purple wire to the OPS and remove the black w/white stripe wire?
Are the pink and blue wires connected properly at the OPS?

Thanks again


Connecting the purple wire to the OPS is how the original circuit was wired. I'm guessing that the black w/white stripe wire was added for a alternate fuel pump circuit?

I think these drawings should help you determine if the pink and blue wires are connected properly at the OPS.

The fuel pump operates under the following two conditions:
1. Ignition in START position, no oil pressure.
2. Ignition in RUN position, oil pressure (engine running)
The two postion oil pressure oil switch controls pump operation. With no oil pressure, during cranking, current from the starter solenoid PURPLE wire feed, goes through the oil pressure switch, to the DK BLUE wire to the ELECTRIC FUEL fuse to the DK BLUE wire to the fuel pump. Once the engine starts, and there is oil pressure, the oil pressure switch directs current from the PINK wire (from the ignition switch) to the DK BLUE wire, through the fuse, and to the pump.

Here are a few more wiring diagrams. Hope this helps. Brian
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Re: Wiring harness issues-need help!

Postby JimW » Mon Nov 14, 2011 5:23 am

Thanks - the diagrams helped!
'64 Buick Wildcat w/401 Nailhead in restoration process
'67 Chevy C20 (son's daily driver)w/Inline 250 - lumps, big valves, Offy intake, Holley carb, Langdon Headers, 240 hp w/ T5
'77 Astre SBC 327 with TPI, Megasquirt EMS, 200-4R
JimW
 
Posts: 98
Joined: Sun Dec 12, 2010 12:42 am
Location: Upstate NY, Binghamton area

1977 Pontiac Astre Hatchback


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