Help - Weird Wiring on Regulator

[kansasc10]

Anybody seen this before? The white and brown wires that are supposed to go to the external regulator plug, (#2 and #4) are spliced together for some reason and Im trying to figure out why and what that would have done to the charging system. Im having battery drain issues and was checking the regulator when I noticed the weird wiring. Just wanted to see if anyone knows why the previous owner might have done this before I go changing it. Im hoping that connecting them back to the regulator plug will fix my issues.
72 C10 w/ 350.

[hotroddin]

Is your current alternator an internal regulated one? It looks like someone did a bypass on the external regulator to do the switch. Check the 2 wires on the plug for your alternator as they are probably spliced as well. If you can't see it, you might have to pull back the tape or whatever else you have 9v er your wires to make sure they aren't spliced. If they are you can reconnect everything to go back to external or leave it like it is.

[vettedrvr]

Originally Posted by kansasc10

Anybody seen this before? The white and brown wires that are supposed to go to the external regulator plug, (#2 and #4) are spliced together for some reason and Im trying to figure out why and what that would have done to the charging system. Im having battery drain issues and was checking the regulator when I noticed the weird wiring. Just wanted to see if anyone knows why the previous owner might have done this before I go changing it. Im hoping that connecting them back to the regulator plug will fix my issues.
72 C10 w/ 350.

Attachment 1427177

I'd say you've been POed. There is no explaining what fools do and nothing is 'foolproof' because fools are so ingenius. Tear that out, switch to a one wire alternator and put in a new engine compartment harness. No PO mess, no electrical drains and no problems.

[kansasc10]

Originally Posted by hotroddin

Is your current alternator an internal regulated one? It looks like someone did a bypass on the external regulator to do the switch. Check the 2 wires on the plug for your alternator as they are probably spliced as well. If you can't see it, you might have to pull back the tape or whatever else you have 9v er your wires to make sure they aren't spliced. If they are you can reconnect everything to go back to external or leave it like it is.

Thats a good question. I assumed it was external but after looking at it, I do believe it may have been switched to internal. When I bought the truck, the plug wasnt even attached to the regulator so I thought plugging it back in would fix my battery drain but that wasnt the case. I guess it wasnt plugged in because it didnt have to be? Can you tell from the picture if its internal or not? Still chasing the battery drain....

[ak808]

Looks like a 10si, internally regulated alternator. Battery drains can be a pain to chase. Can you put an ammeter inline and take out and replace a fuse at a time and see a current draw?

[firedemon]

is it battery drain or not charging if its a drain do the test light trick . disconnect neg side of bat connect one end of light to cable one end to batt then start pulling fuses one at a time till light goes out

[hotroddin]

Was anything added inside that wasn't stock? New radio, gauges, anything that can draw power? If there is I would start with those things first. If you're still having trouble do like ak808 suggested go through one fuse at a time with a volt meter.
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[kansasc10]

Originally Posted by ak808

Looks like a 10si, internally regulated alternator. Battery drains can be a pain to chase. Can you put an ammeter inline and take out and replace a fuse at a time and see a current draw?

Im going to try that next. Started with battery and alt/reg and since they seem to be fine, Ill start pulling fuses.

Fire...its a battery drain. It seems to charge fine when driving around. As long as I drive it, battery stays good. But after sitting for 2 days or so, itll be drained.

Hotroddin....Ive only had the truck for a couple of months and havent added any electronics to it yet. The only aftermarket part I could find was the radio, so I pulled it all out about a week ago hoping that was the solution but battery was dead about 2 days later.

Just to make sure, If it connect a test light to the neg battery cable, and the other end to the neg battery post, it should light if I have a draw. Is that correct?

[firedemon]

yes and it can be very weak if its a slight draw so give it a close look

[swamp rat]

I think whats been overlooked here is that if your internally regulated then that plug should be disconnected from the regulator altogether.

There are FAQ threads explaining how to do this in the electrical section

Read this thread and look at the second pic in post 13, you can see the 4 prong plug and how its jumpered on the 4 connections..

http://67-72chevytrucks.com/vboard/s...ed+converstion

[67 chevelle]

Looks like po tried to do a conversion to a internally regulated alt ,,, the wrong way , do your research but Im pretty sure the 2 outside wires are the ones supposed to be spliced , not the ones pictured in your top post

When these are modified most join the brown and blue wires , and the red and white are capped


READ THIS http://www.madelectrical.com/electrical-tech.shtml

[kansasc10]

Originally Posted by 67 chevelle

Looks like po tried to do a conversion to a internally regulated alt ,,, the wrong way , do your research but Im pretty sure the 2 outside wires are the ones supposed to be spliced , not the ones pictured in your top post

When these are modified most join the brown and blue wires , and the red and white are capped


READ THIS http://www.madelectrical.com/electrical-tech.shtml

I think you may have nailed it! After doing some research it looks like most have spliced the two outside wires together, which isnt how mine was done. In the meantime, I went ahead and bought the Painless Wiring Harness to rewire the entire truck from head to tail. It will be a while before I have time to do the rewire so I am going to try to resplice the v. reg. wires the right way and see if that fixes my drain issues. Thanks to everyone for being such a great help!!

[RichardJ]

>> it looks like most have spliced the two outside wires together..................I am going to try to re-splice the v. reg. wires the right way and see<<


I wouldn't do that. One of the reasons I am always trying to discourage guys from making the swap from the original 10DN to a 10SI or 12 SI is because there is never a shortage of people out there that can tell you how to do it incorrectly.

The voltage regulator plug you have pictures has pins labeled "F, 2, 3, and 4". The wire to #4 (brown) goes to the dash "Gen" light. That wire is now connected to the #2 wire (white) and completes the Exciter circuit for pin #1 on the new alternator. You can see that in the image below. This is one of VetteVet's great images that he has posted here.

His image shows a jumper from pin #3 to pin F. Most guys place that same jumper from alternator pin #2 to the Bat terminal, directly on the SI alternator. Follow the wiring from pin to pin and you should see that it is the same. VetteVet's wiring will provide better regulation, but the other will still work.
See if you have that jumper. If you do, the problem isn't in the wiring as you have it pictured.