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03-18-2021, 06:07 PM | #1 |
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Join Date: May 2013
Location: Utopia
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Wire/Connector ID help
Have a factory solid blue wire with a single pin connector that is unused on my truck. Very curious what it is for. It exits the main engine harness back by the bellhousing mating area on the driver's side. This is on a virgin 77 C10, 350 engine, 3 speed manual transmission.
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03-18-2021, 06:17 PM | #2 |
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Location: Wentworth, NH
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Re: Wire/Connector ID help
Solid blue. Possibly your truck was converted to gauges and that's the oil pressure lamp switch wire.
__________________
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...
And please let us know if and how your repairs were successful. |
03-18-2021, 06:23 PM | #3 |
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Location: Utopia
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Re: Wire/Connector ID help
Good thought but 100% sure this has factory gauges with the OE mechanical oil pressure gauge copper line exiting the block. Maybe the trucks without gauges had an electric oil pressure switch that this wire went to? For the dummy light? And all trucks had the same engine wiring harness regardless of how they were optioned?
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03-18-2021, 06:52 PM | #4 |
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Location: Oklahoma City, OK
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Re: Wire/Connector ID help
77 may be too early but on trucks with electric choke carbs, there was often a connection to an oil pressure switch that kept the choke heater from getting power until there was nominal oil pressure.
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03-19-2021, 12:21 PM | #5 |
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Join Date: Oct 2008
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Re: Wire/Connector ID help
Open up the 1977 GM Light Truck wiring diagrams.
In 1977 the V8 OIL warning lamp was Circuit 31. It's a Dark Blue single wire from the instrument cluster, through the bulkhead, to an overmolded Female Packard 56 connector. The 1977 wiring diagrams show that there was a choke heater oil pressure switch on some models but it was a two terminal switch with Light and Dark Blue wires in one terminal and two Brown/White wires in the other terminal. The four wires on the oil pressure switch connection, for the trucks so equipped, are circuits 901/931 & 141A/141B.
The only other Dark Blue wires in the engine bay are the RH Turn and the Wiper motor.
__________________
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...
And please let us know if and how your repairs were successful. Last edited by hatzie; 03-19-2021 at 12:31 PM. |
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