Ok I installed a GM cs144 alt in my 83 and I'm having some problems. First let me tell you how I wired it. The "sense" wire of the alt plug is hooked straight to the battery, the "Field/Ignition" wire is tied to the red ignition wire from the old voltage regulator, and the "charge" wire is wired to the yellow from the old voltage regulator. With it like this I was getting no voltage at the charge wire and my charge and brake light stayed on. The truck also stayed idling at ~ 2600 rpms. So I farted around with this and ended up bypassing the charge light relay under the glove box and this caused the engine to idle normal and the charge and brake light went dim and I got ~6V on the charge wire. Then I tried putting a switched 12V to the "charge" wire of the alt to to try and get it to charge and this caused the engine to idle really ruff and it didn't seem like the alt was charging. I wonder if I'm missing a ground somewhere when I unhooked the old alt and voltage regulator. I looked through the internet and found a post on marlin crawler with a guy that had the exact same problem with a GM alt but it was 5 years ago and didn't say if it ever got fixed or not. I looked at the wiring diagrams in the FSM to see if I missed something but there is nothing I can see. Need some of the wiser yota-techers to gimme some thoughts on what maybe this is.

 

I have read a number of posts on GM alternator installations and I do not understand why people just do not use the GM single wire units. You disconnect the Toyota Voltage regulator, remove the Toyota alternator, install the single wire GM unit and install a heavy gage wire to the battery and you are done. Almost all Street Rodders use the GM single wire alternators because of the single wire operating feature. What is your GM alternator's rated AMP output? If it is more than 55 AMPs you need to run a heavy gage wire from the alternator "charge" wire directly to your battery positive + post. Your "Field / Ignition" wiring to the RED wire is okay. The "Charge" wire should go to the large White wire that goes to your Voltage Regulator / Battery. The "Sense" wire should go to the Yellow wire (If that does not work connect the "Sense" wire to the large White wire) Let me know how you did after making the changes.

 

I was hoping you would respond lol you are ao knowlegable on these trucks. I honestly wish I had done a gm single wire install now. Be so much easier. The amp is rated for 144 amps and I ran 2 guage wire from to the battery post to account for the amp increase. Same with batt to starter and batt to ground. So I have the the sense and charge wires crossed. Interesting. I will try this tonigt and let you know what happens.

 

I wana clarify something that might be causing confusion. I am referring to the "charge" wire as the charge light/ idiot light in the alt plug labled "L". Thats what I tried connecting to the yellow wire as that is the charge light circuit. You referred the "charge" wire as the heavy gauge wire from the batt post on the alt to the batt itself.

 

okay. The alternator main output wire should go to the Voltage regulator White wire and to a new 8 Gage wire that goes directly to the positive + battery post. (If you used a 2gage wire that is okay) The wiring going to the Red wire on the voltage regulator is fine.
Tell me the Colors, Names (Labels), etc of all the wires called out on the GM alternator and their pupose if known.

 

Ok on this GM alt there is a 4-wire harness. Here is the autozone link. Also in the page there is installation bulletin you can see everything about the alt including description and wiring.http://www.autozone.com/autozone/par...2_191051_4451_

But anyways it has the "S" terminal which is thicker wire used to sense system/battery voltage. Then it has the "F" terminal for field resistor which I am using for the ignition (red wire in regulator harness). Then it has "L" for Indicator/Idiot Light. Then it has a "P" for a phase/frequency/tachometer signal which I'm not using.


Now I just tried it with the L terminal not hooked up and with the S terminal to the battery and it wouldn't charge. Then I tried L terminal not hooked up and with the S terminal to the yellow in the voltage regulator harness and it wouldn't charge.

I have also tried it with L terminal hooked to the yellow in the voltage regulator harness and with the S terminal to the battery and it wouldn't charge.

I also have grounded the alt to the ground connection on the passenger fender to ensure its grounded.

The truck starts just fine but the charge and brake light stay on and ht alt isnt charging. Now there is a big note in that installation bulletin I mentioned that says L activates the alternator and It will not charge without voltage present at L. When I hooked this to a switched +12V to try and activate the alt the truck started idling really ruff and didn't seem to be charging.

 

I wonder if I change the red wire from the voltage regulator harness to the L terminal on the alt instead of F or something. Also here is a screenshot from a pirate post on the "alternator bible" on what has to happen with the F and L stuff.



Here is the link to the pirate thread:
http://www.pirate4x4.com/tech/billavista/Wiring/Part2/

 

Ok so I removed the red ignition wire from the F terminal and moved it to the L terminal. S is still hooked to battery along with battery charge wire from alt. I think it worked. Battery was 12.5V with engine off. Turned it on and went to 13.10V and so far it has slowly climbed to 13.57V I watched the tenths place on the multimeter climb by +1 maybe every 30 seconds to a minute. Also this paper that came in the box with the alt it said to give the alt about 15 mins to fully adjust the voltage regualtor.

However when I turned the headlights on the voltage starting dropping but the battery also doesn't have a lot of charge since I kept running the engine with the alt not working before testing everything.

 

I just checked what you gave me. Tape or cap "P" and "F" wires individually (do not use). "L" wire goes to ignition RED and "S" goes to Battery positive + Post. Forget the "Charging Light" right now and wire everything as above with the alternator battery terminal connected to the battery. See if it charges.

 

See the post above yours. I think it is charging.

 

Ok, make sure it is charging first. Now to your charging light; is it on or off when you are running and charging? The diagram for the alternator shows a method so your Charge Warning light will work. The method shown will not work because Toyota uses a relay with a Diode circuit on the charge warning light. Let me know about the charge warning light status then we will move on to solve that problem.

 

The dash charge light stays on along with the dash brake light.

 

Im pretty sure that the alt is charging now. Before the battery had 12.5V with engine off and after I let it run about 15 -20 minutes and then sit as least 30 minutes the battery voltage is 12.9V

 

Okay. Add another wire off of the "S" terminal on the Alternator and connect it to the Yellow wire on the Toyota Voltage regulator harness going into the truck cab (Yellow wire in the harness should go to the charge light relay coil). Start and run the truck; let me know if the Charge light goes off. (This is a test wire hook up only).

 

Charge light and brake light did go off, however the charge light does not come on with the key in the ignition position and the engine off like it should. The brake light does work in junction with the parking brake as it should. Also my dash back lights are not working either. Not a big deal right now but I wonder if its related to the charge circuit. Hell maybe I popped a bulb.

Anyways the alt is for sure charging. Charged my battery last night since I had drained it working on this running back and forth to autozone (when alt was technically not working) and today the batt voltage came up real quick got up to 14.8V and then backed down to 14.5V (guess it overshot it) and then per ChefYota4x4's idea I removed the negative cable to the battery while it was running and the truck did just fine. Headlights were still bright and do not flicker/pulse .

 

Okay, I wanted to make sure the charge relay and light worked. Remove the addtional wire from "S". Install a second wire from "L" and connect it to the Yellow wire in the harness going to the charge light relay in the cab. Let me know what the charge light does while running, with the ignition off and when you turn the ignition on but the engine is not started.

 

With ignition on and engine off charge light and brake light are off. Same with engine running.

 

Remove all wires from the "L" and the Red ignition wire. Connect a wire from "L" to the Yellow wire that goes to the Charge relay / light. Let me know the status of the Charge light with engine off, ignition on (engine not running) and with the engine running.

 

Charge and brake light stayed on all the time.

 

Also the brake/red light in my tail lights are not working. Turn signal and reverse lights work though.