Regulator Draining battery and othe electrical.

[swamp donkey]

My new truck (to me), is a 69 k5. The battery was not holding a charge so a quick look under the hood revealed a few things. First, at the battery terminal there are three wires, one goes to the starter, another appears to be from the regulator / altenator. and a third smaller one in the same harness as the reg / alt wire that has a small glass fuse (that was missing), so I replaced it.
I checked the voltage at the battery and was barely at 12 volts. Rev the motor and same thing. I looked around a liitle more and discovered that the regulator harness was not plugged in. I plugged that in, and noticed another wires with no fuse (black with white stripe), so I put a fuse in that too.
I then went back and started the truck and for the first time my Stock voltage meter jumped!! Rev the motor and it gets hire. Turn on the lights and it dips. Checked the voltage at the battery and as long as the motor was reved up I could get 14 volts.
Happy as a clam I went to bed. Woke up this morning with a dead, dead, dead battery. Seems that the voltage meter stays on ALL the time now.
Any one out there have ANY SUGGESTIONS?
THANKS.

 

[Skigirl]

Might be a good idea to take a multimeter to the battery and see if it really is the volt gauge draining the battery. If it is, sounds like you got some wires crossed or something grounded out. Maybe the gauge is messed up. But isolate the source using a meter first, then the solution should present itself.

Lots of posts about how to do this if you need step by step. Search for battery drain.

 

[Grim-Reaper]

GREG72 this might be one you can help with better than I can.

Well since this truck is new to you there are a few things you need to check out before going on.
Ok first off do you have a non regulated alternator? Your truck was originaly Equipped with a seperate regualtor where the newer trucks, 73 up, have the regulator built into the alternator. Its VERY comon for the 69-72 to be converted to the newer style alternator and that regulator be bypassed. So first thing you need to do is figure out if you have the new or old style alternator. If you have a new alternator then the plug at the regualtor should have a couple jumpers in it to bypass the old regulator. Go here
http://64.246.42.114/vboard/forumdisplay.php3?s=&forumid=3
that's the 69-72 site. Do a search and there should be several posts showing you how to jumper.
NOW MAKE SURE that you do have the new alternator before jumpering. If you don't have the new style you could dump 20 or more volts of A/C on the battery if you jumper.
Those old style regulators are prone to fail. Should still be able to get one at most parts stores and your right it does sound like one of the Diodes in the rectifye alternatos put out A/C power. A rectifyer is a device that convers A/C power into D/C power and is part of the regulator. This is done with a set of four Diodes. A diode only alows the power to travel one direction and does prevent drain back through the alternator. Your symptoms do seem to indicate one or more of the diodes has failed and is allowing a drain back through the regulator back to the alternator.
Greg anymore tips?

 

[swamp donkey]

Re: GREG72 this might be one you can help with better than I can.

This sounds the most likely, the reg needing bypass. The alt is new, so I will assume that is has reg built in. I will do a search on how to jumper. I hope this helps, I will keep the board updated.

 

[chulisohombre]

if its the new style all you have to do is run a wire from the battery directly to the big single contact on the alternator.it only turns on at a certain rpm to energise so it will not drain the battery unless the alternator has a fault.i got my 100 amp single wire from summit for 89 dollars.make sure you run a thick jumper wire to the battery from the alternator

 

[swamp donkey]

Re: GREG72 this might be one you can help with better than I can.

Well I didn't spend ALL DAY messing with it, but I did waste a few good hours. The final synopsis is this. If I hook up all the wires in their stock config, then remove the fuse from the black wire with white stripe (it lives in the harness that returns to the fuse block, and is only inches away from the regulator) then thae batt does not drain, and volt gauge does not work at all. Put a fuse in and the gauge works, but shows a very high reading when revved (digital voltmeter shows 14.4) and right in the middle at idle. Turn off the key and hit the brakes and you can see the stock gauge dip a little, and we are back where we started. Draining the batt.
So for now, I have the fuse out (by the way, the black and white wire that I pulled the fuse from is the same wire that is in the harness that plugs into the back of my instrument cluster). The car is charging and not draining, but I have no stock voltmeter.
Does anyone know if there is a diode or anything in the stock gauge that may be letting juice flow through? according to the wiring schematic it should be getting a hot from the key on position plus this black and white wire. I'm stumped.