Alternator Replacement Questions

[domenad]

This week I went through the second alternator I've had on my 85 Grand Marquis. The previous one went quietly. This one decided to go out with more of a show, and shorted internally. The connector cooked down to absolutley nothing. I was pretty scared there for a moment, worried that I had created a short while putting in my Polk DB690 rear speakers, but then I rationalized that I would have blown a fuse before cooking up my alternator.

At any rate, I went to summitracing.com and purchased a 100A chrome-plated to replace the remanufactured turd that I had in it. Imagine my surprise when the two connector, five-wire setup that I previously had was reduced to a single wire! I just ran the thing over to the battery junction on a ring terminal and bolted it on. It seems to work fine, and I removed the connectors and threw them away, including cutting a thin 14 or 16 gauge wire that went under the car.

My question is about my dash Amp light. I've reviewed the manual and wiring diagrams for my car, and I can find no wiring to the dash light that does not come off the battery terminal. The diagram shows the light in parallel with a shunt 15 ohm resistor. Does this mean the light will never come on again? Other than periodically putting a meter on the battery, how can I be certain the alternator is running correctly? Also, should I move the alternator connection off of the batter post and down to the solenoid? They are electrically the same point, but I wonder at any unforeseen consequences.

[Archangel]

I have my 130A alternator connected to the solenoid, I've had no problem with it. But your setup is bothering me - apart from the fat wire that hooks up to the alternator post there should be another wire, a rather thin one, that is used for the voltage regulator. Some cars used exernal regulator, others internal, but to the best of my knowledge there has to be something to prevent the alternator from overcharging and thus cooking the battery.

[domenad]

The alternator has an internal regulator, which I am guessing is joined internally. The summit racing site lists this as being "one-wire capable", but tha again does not really make me feel any better.

[mrltd]

It's a single wire alt...internall regulated. I had a powermaster like that and it fell apart.

As for wire placement it doesn't really matter. You could just get an aftermarket voltmeter...

If the alternator isn't working, you'll notice pretty quickly...especially at night! I don't remember the wiring for the light, but you could test it by disconnetcting the alternator while the car is running or taking the belt off and running it for a short time.

[Archangel]

MrLTD, my 3G alternator is also internally regulated, but it has a thin wire from the ECM harness connect to it - is that for the idiot light?

[mrltd]

Dunno...haven't done the 3g upgrade just yet....

[gadget73]

MrLTD, my 3G alternator is also internally regulated, but it has a thin wire from the ECM harness connect to it - is that for the idiot light?

Its probably for keyed power and/or the idiot light. I forget offhand without digging into my wiring diagrams. One wire on the 3 pin voltage regulator plug loops over to the exciter wire, one goes to +12v as "battery sense" but I don't know if the third goes through the idiot light or direct to keyed ignition. I suspect it goes through the light to keyed igniton.