Parasitic amp draw after doing the jumper at the regulator

[trijetal]

I followed the instructions for doing the mod but now I am getting 1.63 amp draw with all power turned off. I found it by accident while looking for a draw from the horn relay. After unplugging the relay I noticed I was still getting a draw. The only other thing I had done was the jumper - so I unplugged it from the alternator and the draw went away.
Does anyone know why that might be happening? I just bought the truck so this is new to me. Thanks in advance.

[MARKDTN]

So you swapped from an external regulator alternator to a 10SI or 12SI internal regulator?

[RustyPile]

MARKDTN makes a very good point. The jumper does not, in itself, magically convert the existing alternator to internally regulated. You have to install the proper alternator.

If you have indeed, installed the proper alternator, disconnect the power lead from the rear of the alternator. If this eliminates the draw, you have a bad alternator. If the draw is still there, disconnect one of the cables from the battery and connect a test light between the battery post and the removed cable. Start pulling fuses one at a time until the light goes out. That will tell you which circuit has the draw.. All of this is done with the regulator jumper installed. Here is a link to the tool I use when searching out parasitic draws.

https://toolaid.com/product/25100

[trijetal]

yes

[trijetal]

That's what I was doing when I found the problem. I don't know if the regulator is correct or not actually. I don't see any ID marks, but it has a white (#1) and a blue wire plugged in and red and black on the case. It looks like others I have seen on youtube. The videos show the jumper wires 1 to 4 and 2 to 3, not like the schematic. Is the 12 SI the model number I should be using? This one looks like it but looks can be deceiving.

[trijetal]

I finally got it thru my thick skull that apparantly the alternator on this truck IS externally regulated. What started it all was the alternator was not charging even though it checked ok at autozone. I'll order the correct alternator. Thank you all so much for the help. The folks here are a wealth of information.

[RustyPile]

Originally Posted by trijetal

I finally got it thru my thick skull that apparantly the alternator on this truck IS externally regulated. What started it all was the alternator was not charging even though it checked ok at autozone. I'll order the correct alternator. Thank you all so much for the help. The folks here are a wealth of information.

Easy to tell the difference. There are other differences but this is what I look at.. The two male terminal connectors near the front are parallel to each other for EXTERNAL regulator. They line up in a row for INTERNAL regulator..

[EDIT} here's a link to a site that will help you identify AC Delco alternators.
http://www.madelectrical.com/electri...elcoremy.shtml

Using an adaptor plug at the regulator plug and another one at the alternator is kind of a make shift way of making the modification.. The proper way is to modify the wiring harness, add a one or two gauge bigger charge wire at the back of the alternator, and eliminate the extra wiring connecting the original regulator to the alternator.. Do a thread search on this forum, there's been lots of write ups about installing internally regulated alternators.

[trijetal]

Thanks for the help. At least it's fun to work on, and trying to sort out the wiring is going to be interesting.

[RustyPile]

Something I noticed while reading your posts. A few times you referred to alternator as the "regulator" and a couple times, you did the same when referring to the regulator, you called it "alternator".. When you do that, it confuses the reader. Please watch and use the correct terms.

There are numerous forums on this site. They're all listed down the page where you found this forum. Go to the ELECTRICAL forum and find the wiring diagrams thread near the top of that page. Download the wiring diagram for your truck, you'll need it..

Here's a link to a thread that discusses a 12SI alternator, and how to modify the harness for that alternator..
http://67-72chevytrucks.com/vboard/s...d.php?t=800471

[LockDoc]

-
Another way to find the different forums is to scroll down to the bottom of this page (or any page) and click on the arrow in the "Forum Jump" box. Then you can scroll through all of the forums and just click on the one you want to go to.

LockDoc

[trijetal]

Rustypile - thanks. So much for previewing my own posts.

Lockdoc thanks for the info.

I put the plug back in the regulator and returned the circuit to what was there when I started. The alternator is only putting out 12.3 volts when tested with a multimeter, and red lead on alternator "Bat" post and black on the alternator case. Autozone tested the alternator and said it passed the test. It doesn't seem like enough voltage to me keep a battery charged.

[pjmoreland]

If your alternator tested good, then maybe your voltage regulator is not working. The original one in my truck had a set of contacts inside that were fused shut. In my case though, the output of the alternator would go way up to over 18V when revving the engine. I decided to eliminate the external voltage regulator, and went with a 12SI alternator instead. There's some information in the following thread about testing an external voltage regulator.

http://67-72chevytrucks.com/vboard/s...ad.php?t=21734

[MARKDTN]

It's pretty easy to change to a 10SI or 12SI internal regulator alternator and do the jumper mod. If the alternator is good but the old regulator is bad you can swap to a Ford solid state regulator and get rid of the mechanical style (you will need the junkyard plug). If your truck is pretty stock and you don't need extra amperage for fans or big stereo, I would change to the internal regulator style. If you need extra amps, then CS144 swap is the way to go (I do not recognize the CS130 as anything but a paperweight).

[Fbks_Cruiser]

The 10SI alternator isn't great at charging while idling. Try bumping up the engine speed a bit to see what the voltage output is. An easy fix to replace the old mechanical external voltage regulator is use a solid state one like the VR715 at autozone:

https://www.autozone.com/batteries-s...715/130005_0_0

I used one in my truck before I made the switch to a 12SI alternator. Didn't fix the low engine RPM charge problem but they are an easy plug and play swap if your regulator is iffy.

Changing over to a 12SI made a big difference in the charge at idle speed. No more dimming lights when sitting at a stop light. There are lots of forum threads about it.

[trijetal]

Thanks, and I agree. Just working through the problems one at a time.