Quote:
Originally Posted by RustyPile
I'm assuming you have the buss bar installed near the battery?? If so, you have the voltage sense wire terminated in the wrong place.. It should terminate farther "up" the main power distribution wire.. Somewhere near the firewall bulkhead connector.
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Good call. I do believe it's ran all the way over to the busbar, it's just been a while since I wired it up. I'll see about terminating it closer to the bulkhead.
Quote:
Originally Posted by dmjlambert
Check how much voltage drop you get with accessories running at both sides of the firewall bulkhead connector. You probably have a 10 or 12 gauge red wire going into a position on the bulkhead connector. Measure it there by inserting your test meter probe into the back of the connector to make contact with the terminal. This is done while the bulkhead connector is connected to the firewall. Inside the cab repeat measuring at the connector. There's not anything to tearing apart the fuse panel, no biggie. It just fastens to the firewall with 2 screws and you move it out of the way to gain access to the firewall connector. While you have it unfastened, you can make measurements of voltage at the terminal connections on the back side of the fuse panel. I think you'll be able to figure out the main cause of the voltage drop. It's probably one of the connectors if I had to guess. It might need a cleanup of the connector.
I've been rolling it around in my head about how best to get the main power wire voltage into the cab without relying on just one position of the bulkhead connector, to improve the wiring in my truck. I haven't settled on any plan yet.
With all that said, the voltage drop is probably not a serious concern unless it's actually causing you problems. If it's just causing you worry, that may not be enough. These trucks were not engineered to have stellar electrical systems. So, you could power the gauge from the original black/white wire previously going from the alternator to the ammeter you replaced, or power the gauge from the original black/brown wire previously going from the battery to the ammeter you replaced. One of those wires will probably give you a better and more steady gauge reading.
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I'll have to do some more probing this weekend, we got hit with rain for the last two days. I agree it's not a serious concern, except that when voltage drops on the distributor i assume it's affecting spark voltage and possibly causing the engine to load up more at idle than it usually would otherwise, when accessories are running. It's not a problem i'm chasing daily, but I always default to making sure current wiring is tip-top before adding stereo or additional accessories.
Quote:
Originally Posted by bhap
I'd suggest upgrading the wire size from your buss bar to the fuse box and maybe adding relays for your headlights. The headlights are easy to wire from your buss bar to a relay using the original low and high beam power wires to trigger the relays. The other point mentioned above is the bulkhead connectors. Resistance causes voltage drops and heat. I've seen connector plugs that have melted from poor connections. Any other accessory you can power from a relay will take stress off the rest of the harness. I'm a big fan of madelectrical.com - lots of good information.
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I do have headlight relays, and the main harness wire from busbar to bulkhead has been upgraded to a 10ga. It's impossible to get the physical connection into the bulkhead with 8ga or larger with the original style packard terminals. I don't plan on running ANYTHING additional not equipped in 72 through the original harness, with the exception on the Alt and HEI upgrades. I'll run anything additional from the battery to a new fuse panel and or relays.
a little more info- Any time i disconnect a harness or connector, I unpin each connection and clean it with a wire brush before reconnecting with a touch of dielectric grease.
Thanks for all the help so far. Fantastic community as always