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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: jman340 on March 29, 2013, 04:53:01 pm

Title: Tank selector switch power
Post by: jman340 on March 29, 2013, 04:53:01 pm

I'm working on my 86 GMC 1500 that had a holly projection unit on it when I got it. I've taken that out and put a carb in it's place. Now I'm having some trouble with the selector switch not working. There is a solid pink wire that was attached to the projection controller coming from the tank selector switch. The installation was pretty much a hack job, so I'm having trouble finding where this originally terminated. Can anyone help? I assume that it's a 12 volt source, but don't want to hook it up blindly. Any help would greatly be appreciated.

Thanks

Title: Re: Tank selector switch power
Post by: hatzie on March 29, 2013, 06:20:05 pm

The pink wires in the dual tank circuit are the gauge on plug pins A, B, & C.  Pink with tracer stripes should run from the senders to A & C on the valve and solid pink should run from B on the valve to the bulkhead plug on the firewall. 
I'm not sure what the ProJection system would've used the fuel gauge wire for :o ???  I'd eBay/Craigslist the ProJection setup.  Someone will want it.

These are the 1986 GM CK schematics.  In the bottom center pane on page 16 is the NL2 dual tank sub-harness schematic as originally installed.  http://johnnynightstick.s3.amazonaws.com/GM/Wiring/ST_352_86_1986_Chevrolet_GMC_Light_Truc_Wiring_Manual_CK_10_30_Only.pdf (http://johnnynightstick.s3.amazonaws.com/GM/Wiring/ST_352_86_1986_Chevrolet_GMC_Light_Truc_Wiring_Manual_CK_10_30_Only.pdf)

Title: Re: Tank selector switch power
Post by: jman340 on March 30, 2013, 10:50:43 am

Thanks,
I tried to open the file, but is stops loading at page 9. Anyone else have a good schematic?

Title: Re: Tank selector switch power
Post by: jman340 on March 30, 2013, 11:17:47 am

Got it. Looks like the pink wire was attached to the fuel pump relay. I ran it to a 12 volt source and it worked as it should.