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Old 07-16-2018, 11:36 AM   #1
Pontiac1976
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what this plug for?

I had this loose in the bay since I changed the wiring. I never come across it when looking so far.

Not sure if this one of the optional wires for the 700R4 hook up.

Because I have factory dual set up on this wiring harness both Dist. 4 pin & 5, & the 700R4 trans.


1984 GMC 305 700R4 1/2Ton

Where does this go to?.


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1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
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Old 07-16-2018, 12:25 PM   #2
Justins76
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Re: what this plug for?

EGR solenoid?
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Old 07-16-2018, 07:55 PM   #3
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Re: what this plug for?

The EGR is vacuum operated. I do not think there was a solenoid on it that I know.
where was the solenoid located ?
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1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
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Old 07-17-2018, 06:04 AM   #4
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Re: what this plug for?

Quote:
Originally Posted by Pontiac1976 View Post
The EGR is vacuum operated. I do not think there was a solenoid on it that I know.
where was the solenoid located ?
An 84 305 came with an EGR solenoid from the factory. It would help control vacuum going to the EGR valve. It was located to the right side(passenger side) of the distributor.
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Old 07-17-2018, 07:23 AM   #5
hatzie
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Re: what this plug for?

EGR solenoid has different color wires and a different connector.

Harness came from a Manual transmission truck?

The ESC 1st gear switch on a 1984 manual transmission truck has a two-terminal Weatherpak with Green and Yellow wires. Yellow goes back to the ignition Crank wire just before the Clutch interlock and Green goes to the ESC computer.
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Last edited by hatzie; 07-17-2018 at 07:28 AM.
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Old 07-17-2018, 11:19 PM   #6
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Re: what this plug for?

hatzie Qoute:EGR solenoid has different color wires and a different connector.

Harness came from a Manual transmission truck?

The ESC 1st gear switch on a 1984 manual transmission truck has a two-terminal Weatherpak with Green and Yellow wires. Yellow goes back to the ignition Crank wire just before the Clutch interlock and Green goes to the ESC computer.

Answer: The Truck is a 84 GMC 305 Auto, None A/c Truck had duel set up Dist. set ups 84 had a TH350 in it no motor. I got the cab, clip witch the clip is mostly on my 77
and the wiring harness still has the computer. I have not seen the connector before yet. I not sure if it's a Factory Plug. Wire green & yellow look's like 14ga
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1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.

Last edited by Pontiac1976; 07-20-2018 at 12:38 AM.
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Old 07-21-2018, 06:59 AM   #7
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Re: what this plug for?

I wonder if the truck had dual wiring Trans set up too, since it had dual Dist. wiring set up too. That would explain why most 84 trucks when I was looking for it was on A/T
not a lot truck had this set up.
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1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
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Old 07-22-2018, 07:36 PM   #8
hatzie
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Re: what this plug for?

Download the 1984 wiring diagrams. Not very many Weatherpak plugs in that year harness period.

Get your meter out and set it up as a continuity buzzer.
Does the yellow wire ring out the neutral safety switch?
Does the green wire ring out to the ESC computer?
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
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Old 08-22-2018, 11:23 PM   #9
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Re: what this plug for?

Quote:
Quote: hatzie Harness came from a Manual transmission truck?

The ESC 1st gear switch on a 1984 manual transmission truck has a two-terminal Weatherpak with Green and Yellow wires. Yellow goes back to the ignition Crank wire just before the Clutch interlock and Green goes to the ESC computer.
Good call had time test start taking it out. And it turn out that it is set up for Dual trans wiring for A/T and M/T backup light. 700R4 wiring, Dual Dist. wiring. I'm really happy I grabbed this wiring harness did the 84 change over.
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1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
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