Wiring woes, manual tranny wiring to automatic - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Your41Plague12 · 01-14-2013, 07:31 PM

Ok here's my deal. This is kind of confusing, so bear with me. I bought a cab for my truck, it's from an 84 C10 with an SM465, the truck it's supposed to end up being is an 83 GMC K2500. I am using the wiring harness from the C10. How do I make this work with my automatic column, i.e. neutral safety switch and such? What will I do for reverse lights, as well? The harness is stock, and relatively uncut. The only cut wires were the ones for the rear of the chassis. Thanks!

Steve

ray_mcavoy · 01-14-2013, 07:51 PM

Check the wiring diagrams that hatzie posted at http://67-72chevytrucks.com/vboard/s...d.php?t=545416 to be sure, but I believe the cab/under-dash harness in these trucks is the same for all transmissions.

The manual trans will have a clutch safety switch that prevents the starter from cranking unless the clutch pedal is pushed all the way to the floor. I think you can simply unplug the connector from that switch and plug it directly into the auto trans neutral safety switch.

The manual trans reverse lights usually have an extension harness that runs from the under-dash harness down to the switch on the trans. I think you can simply unplug that from up under the dash and plug the reverse light connector into the auto trans reverse light switch (which is combined in the same housing with the neutral safety switch on the auto trans steering column). The two plugs (neutral safety & reverse lights) are shaped differently so each one will only plug into the corresponding spot on the switch.

Your41Plague12 · 01-14-2013, 08:01 PM

Ok, so basically all the wiring should be in the manual transmission harness to make the automatic work? It's plug and play? That's great news. I tried looking through the wiring diagrams, but I'm not much of an electrical wizard.

ray_mcavoy · 01-14-2013, 08:09 PM

Yes, it should be pretty much plug and play ... so long as the wires are long enough to reach to the auto trans neutral safety switch and I think they are.

For the clutch/neutral safety start switch you're going to be looking for a pair of fairly heavy gauge wires (yellow and purple) that go into a somewhat square shaped plug. And for the reverse lighs you're going to be looking for a pair of lighter gauge wires (dark blue and light green) that go into a rectangular shaped plug. Both of these should be located in the under-dash harness somewhere close to the steering column.

01-14-2013, 07:31 PM	#1
Your41Plague12 Registered User Join Date: Dec 2010 Location: Pittsburgh, PA Posts: 1,009	Wiring woes, manual tranny wiring to automatic Ok here's my deal. This is kind of confusing, so bear with me. I bought a cab for my truck, it's from an 84 C10 with an SM465, the truck it's supposed to end up being is an 83 GMC K2500. I am using the wiring harness from the C10. How do I make this work with my automatic column, i.e. neutral safety switch and such? What will I do for reverse lights, as well? The harness is stock, and relatively uncut. The only cut wires were the ones for the rear of the chassis. Thanks! Steve __________________ Steve Member of the Foot Pedal Club '83 Chevy K20: 6" Rough Country, 3" Performance Accessories BL, Bushwacker Cutouts, 38x15.50 Mickey Thompson Baja Claws, 350 HP 350 crate engine from Jegs, Turbo 400

01-14-2013, 07:51 PM	#2
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,359	Re: Wiring woes, manual tranny wiring to automatic Check the wiring diagrams that hatzie posted at http://67-72chevytrucks.com/vboard/s...d.php?t=545416 to be sure, but I believe the cab/under-dash harness in these trucks is the same for all transmissions. The manual trans will have a clutch safety switch that prevents the starter from cranking unless the clutch pedal is pushed all the way to the floor. I think you can simply unplug the connector from that switch and plug it directly into the auto trans neutral safety switch. The manual trans reverse lights usually have an extension harness that runs from the under-dash harness down to the switch on the trans. I think you can simply unplug that from up under the dash and plug the reverse light connector into the auto trans reverse light switch (which is combined in the same housing with the neutral safety switch on the auto trans steering column). The two plugs (neutral safety & reverse lights) are shaped differently so each one will only plug into the corresponding spot on the switch.

01-14-2013, 08:01 PM	#3
Your41Plague12 Registered User Join Date: Dec 2010 Location: Pittsburgh, PA Posts: 1,009	Re: Wiring woes, manual tranny wiring to automatic Ok, so basically all the wiring should be in the manual transmission harness to make the automatic work? It's plug and play? That's great news. I tried looking through the wiring diagrams, but I'm not much of an electrical wizard. __________________ Steve Member of the Foot Pedal Club '83 Chevy K20: 6" Rough Country, 3" Performance Accessories BL, Bushwacker Cutouts, 38x15.50 Mickey Thompson Baja Claws, 350 HP 350 crate engine from Jegs, Turbo 400

01-14-2013, 08:09 PM	#4
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,359	Re: Wiring woes, manual tranny wiring to automatic Yes, it should be pretty much plug and play ... so long as the wires are long enough to reach to the auto trans neutral safety switch and I think they are. For the clutch/neutral safety start switch you're going to be looking for a pair of fairly heavy gauge wires (yellow and purple) that go into a somewhat square shaped plug. And for the reverse lighs you're going to be looking for a pair of lighter gauge wires (dark blue and light green) that go into a rectangular shaped plug. Both of these should be located in the under-dash harness somewhere close to the steering column.



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