Trouble with voltage drop

[RustyPile]

Originally Posted by leftybass209

Update: the issue is fixed.

It wound up being the fuse panel power wire being too long. After taking the suggestion above of moving the sensing wire, i still didn't move the harness feed. The excessive length was enough to cause a significant voltage drop on all accessories that got exponentially worse as accessories were added. I bought larger packard terminals to run a larger gauge wire into the factory harness, but it physically didnt fit between the plastic and lock in, so my wire was limited in gauge.

I still have some small stretches of cca wire needing to be replaced bit overall this has made an amazing difference on voltages seen at the accessories.

I discovered this after reading the M.A.D electrical page regarding chevy wiring harnesses.

Thanks for the suggestions

As for the issue of getting a large gauge wire to attach to the terminals at the firewall connectors.. Here's what I did.. I upgraded the main power distribution wire from the buss bar near the battery to the firewall connector.. I ran a 10 gauge wire to a point about a foot just shy of the firewall. At that point, I spliced in two 12 gauge wires long enough to reach the firewall connector along with the alternator sense wire. I connected one of these wires to the "socket" where the 12 gauge wire originally connected.. I connected the other wire to a blank, unused "socket"..

Inside the cab, I separated the main power feed at the junction where it splits and feeds the headlight switch, fuse box, ignition switch and horn relay. I connected the horn relay feed and headlight feed together and put a terminal on it and plugged it into (doesn't matter which one) one of those two main power "sockets".. I connected the feed for the fuse box and the feed to the ignition switch together and put a terminal on it and plugged the wire into the other main power "socket".. This modification divides the amperage flow into two separate terminals at the firewall connector.. If nothing else, this eliminates the need for headlight relays.