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Old 07-10-2017, 05:40 PM   #1
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Join Date: Jul 2017
Location: Highlands Ranch, CO
Posts: 39
Question Rewired 70 C10 heater and running lights on even if ign is not plugged in.

Thanks to all on this forum as I have gotten a lot out of it but am unfortunately still stumped because of my lack of knowledge/experience with auto wiring.

I have a 1970 C10 shortbed that I bought a brand new AAW harness for and have also upgraded the gauge kit (New Tach, Clock). I have installed it per instructions and all of the wires are marked making it fairly easy to tell what is what. On my first attempt to connect the battery, I burned out to wires on the printed circuit (alternator circuit, and "terminal next to battery" circuit. It was tedious but I was able to splice together the old board and the new board for a completed circuit that would fit around the tach. The issue was that the AAW diagram showed a pink IGN wire and a GROUND going to the BAT gauge but I now know that is not how these C10s are wired. Even though the circuit board fried, the heater, electric fan, and front and rear running lights were on in the key's OFF position.

Thanks to VetVette (who I hope doesn't chastise me too much for posting) and others on this forum, I was able to wire up the gauges correctly and the circuit board seems to be intact. However, the heater and running lights still come on after I hook up the battery (I unplugged the electric fan). After some reading I thought that one of the wires on the ignition was staying hot but I have them wired individually so I pulled them off one at a time and the heater and lights still stayed on. The dash lights (connected), the brake lights, and the reverse lights don't come on with their respective triggers though. Some notes below on the components:

Ignition switch and wiper switch = old
Headlight switch = new
Electric fan came with a relay mounted next to the battery that acts as a circuit breaker. Battery cable has extra wire to hook into relay.
Battery is hooked directly to starter with red harness feed and purple IGN wire
Power side of relay by the battery has been run to the BAT side of Battery gauge and spliced to number 12 wire on dash cluster plug
A/C Heater lamp did not have a specific wire so left out. Still not sure if that little lamp completes a circuit or not, would need to splice if so.
The voltage regulator has been deleted from the harness
Haven't connected courtesy ground wire (currently capped) to anything yet as I need to wire dome switches

Thanks in advance for any information.
I appreciate any help that this forum can provide. Thanks!
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