Another alternator question

[superpowerdave]

Don't groan too loudly

Many of you know I picked up this 109 that was converted to diesel just before I deployed and am working on getting her into running condition. The alternator had been installed, but I don't think it had been wired properly because I've got a charging issue that I'm really interested in working out.

I've looked at countless diagrams and suggestions, have had electric-smart people over to help me pore through it but each time we come up empty ... the thing just won't charge.

The alternator and battery have been ruled out and tested.

Basically on the voltage regulator I have more wires and spades than depicted on wiring schematics and diagrams so that's thrown me for a loop.

A1 - two wires jumped together - one goes to the light switch on the dash, and the other to A1 fuse.

A - only one wire here where my diagram shows two - the one wire goes to the red inspection socket. Since the other wire that should be there would go to the horn it would explain why the horn isn't working.

F - goes to charge warning lamp and the oil pressure warning lamp - these two are jumpered together as well.

D - goes to Amp meter.

On one of the smaller back spades there is also a black wire that leads who knows where. The vehicle runs just fine, just doesn't charge. If I leave the battery on the trickle all night she fires right up. A few times later in the day though if I start her up she'll fire up just fine, and then if I turn her off and then go to restart her minutes later she won't budge without a jump.

I'm hoping somebody has some answers. What I'd really like to do is circumvent the regulator entirely, but don't know if that's an option. After pulling the regulator I do know it's bad as one of the metallic strips is blown through.

ANy help or a highly detailed picture of what I need to be doing would be greatly appreciated.

[Nium]

What alternator do you have installed? How many wires coming out of it?

[greenmeanie]

Has anyone checked the AMP gauge?

THey are horrible things that take the full electric flow and seperate your battery from the alternator. Note that your starter is on the battery side of the gauge so will still work and alllow the engine to run without the rest of the sytem functioning.

My personal preference is to remove them from the circuit. A volt gauge will tell you more useful infomration about your electric system than a amp gauge and won't effect reliability.

A link on why.

Check for volts at the A terminal of the regulator to eliminate the amp gauge.

Your alternator will do nothing electrically unless the field wire has power. On your truck it receives power through a rather convoluted path from the battery – amp gauge to A terminal – A1 terminal – A terminal on ignition switch – ign terminal on ignition switch – charge light – F terminal on regulator. With the ignition switch on check for volts at each of these points and I’ll be you find the problem.

Now your description does not make this clear. You need the A terminal to be jumped to the A1 terminal for any current to get to the ignition switch.

Without knowing what unit you have used for your conversion I cannot be definite but most alternators feature internal regulation. If you are using the common swaps of a Delco 10SI/12SI or a LUCAS 16ACR he voltage regulator you're looking at is now just a very fancy terminal strip in which case any internal problems can be ignored.

[I Leak Oil]

http://www.lrfaq.org/Series/FAQ.S.alt_alternators.html

This is a good article on the typical GM conversion. You need to ditch the external regulator. Make sure you are looking at the correct wiring diagram for your truck's original configuration. If it was originally a petrol then make sure you're looking at the schematic for a petrol.

And Greenie is right, get rid of the ammeter. It will only cause you pain....and smoke....

[Donnie]

Don't groan too loudly

Many of you know I picked up this 109 that was converted to diesel just before I deployed and am working on getting her into running condition. The alternator had been installed, but I don't think it had been wired properly because I've got a charging issue that I'm really interested in working out.

I've looked at countless diagrams and suggestions, have had electric-smart people over to help me pore through it but each time we come up empty ... the thing just won't charge.

The alternator and battery have been ruled out and tested.

Basically on the voltage regulator I have more wires and spades than depicted on wiring schematics and diagrams so that's thrown me for a loop.

A1 - two wires jumped together - one goes to the light switch on the dash, and the other to A1 fuse.

A - only one wire here where my diagram shows two - the one wire goes to the red inspection socket. Since the other wire that should be there would go to the horn it would explain why the horn isn't working.

F - goes to charge warning lamp and the oil pressure warning lamp - these two are jumpered together as well.

D - goes to Amp meter.

On one of the smaller back spades there is also a black wire that leads who knows where. The vehicle runs just fine, just doesn't charge. If I leave the battery on the trickle all night she fires right up. A few times later in the day though if I start her up she'll fire up just fine, and then if I turn her off and then go to restart her minutes later she won't budge without a jump.

I'm hoping somebody has some answers. What I'd really like to do is circumvent the regulator entirely, but don't know if that's an option. After pulling the regulator I do know it's bad as one of the metallic strips is blown through.

ANy help or a highly detailed picture of what I need to be doing would be greatly appreciated.

Go to a GM 10si unit, regulator is built in ...add a volt meter. unless U R wanting to stay OEM..then follow the instructions of others ...Donnie

[superpowerdave]

Alternator is a 3-wire, unsure of the brand. There is a spade connector that has two wires coming out of it and one wire coming out of the casing of the unit. One of the wires coming from the spade is lopped back around and connected to a lug on the back of the unit. The other two are the only ones used in the current wiring set up.

After much testing and connecting and crimping, I was able to get it wired properly and charging save for one issue - the charging light comes on when I turn the truck off?

When I get in the truck the charging light is on, and distinguishes shortly after the engine is revved. It remains off the entire time the truck is running, but then lights up when the engine is turned off.

Does this make any sense to anyone? Thanks again for the responses.

[brucejohn]

It sounds like the alternator warn lamp isn't wired into the ignition switch circuit correctly. It should be on a circuit that is only open when the key is turned on. I think typically, it is wired straight from alternator > lamp > common post (clinch connection) with the oil warn lamp and cold start warn lamp > ignition switch.

Tracking down all this electrical stuff can drive a person nuts. Good luck.

[Rineheitzgabot]

It sounds like you have the GM model.

There are two wires coming from the plug, and one coming off the post that is on the back of the case.

Here is the purpose of the wires:

White, 14ga out of plug: "sense" wire that tells the alternator to put out more or less electricity depending on the demand.

Red, 14ga out of plug: This wire gives the alternator the ability to work. It should be connected to switched 12V.

Whatever color wire attached to lug on back of alt case, but should be at least 10ga: This wire is responsible for charging the battery and should be attached somewhere in the circuit that comes in direct contact with the battery.

If the large wire coming off the lug on the back of the alternator is unhooked, the unit will not charge.

This is rough theory, but should shed some light to the issue.