1976 Wiring help! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

74CustomK20 · 12-11-2014, 09:39 PM

Well I got my 76 wiring harness back finally! (Thanks old rusty c10!) But with used parts always poses this problem... I'm outta my league lol. The rear harness has 3 bulbs per side n 1 small one... not 2 big n one small like my 85 fleetside. Also has 2 wires with gromets?
This truck had idiot lights I can tell ( has electric oil pressure wires) and I want guages. Need help with differences there guys... I guess after that... A link to a 76 wiring manual? Hope to get this harness in over x-mas break from work.

**hatzie** · 12-12-2014, 12:31 AM

Using a later 77 1/2 to 80 all-electric gauge panel is easier when you start with warning lamps...
A GM wiring manual is easy... Look down

You'll need the wiring manual for your donor Instrument panel and the wiring manual for the 76.

Unless someone has added amber turn signals with an independent brake lamp wire there are only four circuits.
RH turn/brake, LH turn/brake, backup lamps, and parking lamps.
All your side marker lamps, tailgate lamps, clearance lamps, and license plate lamps will run off the parking lamp circuit.
I have extra LED backup lamps buried in the bumper that run in parallel with the stock lamps... They are still the same circuit.

74CustomK20 · 12-12-2014, 10:37 AM

Actually hatzie you were the first person I thought of and downloaded the manual. Problem is afterward of 100% it says problem downloading and won't let me open it. I did find one on eBay for 20 bucks so gonna get it... I think I'll find a use for em eventually. Next if forward lighting and engine followed by in cab. I'll add lots of pics tonight to try n help...

**hatzie** · 12-12-2014, 11:33 AM

I uploaded new copies and repaired the links. I'll have to check all of them. Looks like Mediafire has some file corruption going on.

74CustomK20 · 12-13-2014, 10:40 AM

Thanks hatzie again. The 76 worked and from the way I read it, it has a 3 piece junction block. My harness from rusty has only a 2 piece junction block. Engine side and headlight side... It's really confusion g haha. Thinking of just making a custom harness out of my... 5? Harnesses available... 73, 74, 77, 78, and a 79 harness... Very confusing.

74CustomK20 · 12-17-2014, 09:41 PM

Update of sorts. I am going to use the 74 in dash wiring harness as it IS for guages and in very good shape. I will modify the outside harness to work with that as needed. Also ordered a 74 wiring manual off ebay so hope it gets here soon.

12-11-2014, 09:39 PM	#1
74CustomK20 Registered User Join Date: Oct 2014 Location: Tell City, IN Posts: 637	1976 Wiring help! Well I got my 76 wiring harness back finally! (Thanks old rusty c10!) But with used parts always poses this problem... I'm outta my league lol. The rear harness has 3 bulbs per side n 1 small one... not 2 big n one small like my 85 fleetside. Also has 2 wires with gromets? This truck had idiot lights I can tell ( has electric oil pressure wires) and I want guages. Need help with differences there guys... I guess after that... A link to a 76 wiring manual? Hope to get this harness in over x-mas break from work. __________________ Big Nate Carp. Local 224. Buy made in the USA! 03 F350 6.0 Daily Race Truck. 79 C70 366 Project Dump.

12-12-2014, 12:31 AM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,930	Re: 1976 Wiring help! Using a later 77 1/2 to 80 all-electric gauge panel is easier when you start with warning lamps... A GM wiring manual is easy... Look down You'll need the wiring manual for your donor Instrument panel and the wiring manual for the 76. Unless someone has added amber turn signals with an independent brake lamp wire there are only four circuits. RH turn/brake, LH turn/brake, backup lamps, and parking lamps. All your side marker lamps, tailgate lamps, clearance lamps, and license plate lamps will run off the parking lamp circuit. I have extra LED backup lamps buried in the bumper that run in parallel with the stock lamps... They are still the same circuit. __________________ 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... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF 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.

12-12-2014, 10:37 AM	#3
74CustomK20 Registered User Join Date: Oct 2014 Location: Tell City, IN Posts: 637	Re: 1976 Wiring help! Actually hatzie you were the first person I thought of and downloaded the manual. Problem is afterward of 100% it says problem downloading and won't let me open it. I did find one on eBay for 20 bucks so gonna get it... I think I'll find a use for em eventually. Next if forward lighting and engine followed by in cab. I'll add lots of pics tonight to try n help... __________________ Big Nate Carp. Local 224. Buy made in the USA! 03 F350 6.0 Daily Race Truck. 79 C70 366 Project Dump.

12-12-2014, 11:33 AM	#4
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,930	Re: 1976 Wiring help! I uploaded new copies and repaired the links. I'll have to check all of them. Looks like Mediafire has some file corruption going on. 1976 ST330-76 1976 Chevrolet Light Truck Service and Overhaul Manual Supplement 1976 GM CK Light truck Wiring Manual __________________ 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... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF 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.

12-13-2014, 10:40 AM	#5
74CustomK20 Registered User Join Date: Oct 2014 Location: Tell City, IN Posts: 637	Re: 1976 Wiring help! Thanks hatzie again. The 76 worked and from the way I read it, it has a 3 piece junction block. My harness from rusty has only a 2 piece junction block. Engine side and headlight side... It's really confusion g haha. Thinking of just making a custom harness out of my... 5? Harnesses available... 73, 74, 77, 78, and a 79 harness... Very confusing. __________________ Big Nate Carp. Local 224. Buy made in the USA! 03 F350 6.0 Daily Race Truck. 79 C70 366 Project Dump.

12-17-2014, 09:41 PM	#6
74CustomK20 Registered User Join Date: Oct 2014 Location: Tell City, IN Posts: 637	Re: 1976 Wiring help! Update of sorts. I am going to use the 74 in dash wiring harness as it IS for guages and in very good shape. I will modify the outside harness to work with that as needed. Also ordered a 74 wiring manual off ebay so hope it gets here soon. __________________ Big Nate Carp. Local 224. Buy made in the USA! 03 F350 6.0 Daily Race Truck. 79 C70 366 Project Dump.



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