Looks like my generator has gone bad. I was thinking about an alternator upgrade anyway since I will be pulling a trailer with lights and electric brakes.

What off-the shelf (new) alternator would be the best? One consideration is, I'd like the gen idiot light on the dash to still work.

I read that the GM 10SI is a popular choice, and is a one wire. Can this be set up so the idiot light works?

Thanks,

Phil

 

I used a one wire on mine, and it works great. I don't know about the idiot light, I bought a speedo out of a Bronco, so I could have full gauges.

 

I have the GM alternator in mine. It work amazingly, I am very very happy with it. The old generator sucked... worse than a shop vac. I think it is possible to make it work with an idiot light. My uncle is an engineer for microsoft and he said it was easy to do, but I didn't bother with it.

I really recommend the alternator over the generator. It cost about the same as the generator, but work an infinite times better. You kinda need an imagination to get it mounted. I was able to mount it in the same spot as the generator and use the same belt.

 

You can have an idiot light, or you can have a 1 wire. But not both.
The 1 wire is a lot easier to install because of the minimal wiring. Occasionally, a side effect is you have to rev up a few R's to initialize a self exciter, particularly the higher amp ones. Some guys install a voltmeter so they know what's going on.... If you go with the stock 7127 alt. (part store GM 63amp). You'll see "1.R" and "2.F" on the casting near the plug. Run a #10 wire from "2F" to the output post on the alt. Run the output post on the alt. to Battery + through some #12 fuse link wire. Then run a wire from "1R" on the alt to one side of the idiot light. Come out of the other side of the idiot light and go to the ignition switch. (find a terminal that is off/on with key in run position.

 

If you get a Tuff Stuff 7068 it is a GM style 100 amp ALT one wire with Ford Mountings, it also has a provision for the idiot light. I used a Number 8 wire from the hot lead on the Alt to the Battery positive terminal, then I ran the idiot light wire , which if I recall is an orange wire, to the terminal on the Alt which is under a removable rubber plug, I removed all of the other wires that ran to the Voltage reg. I spent more time taking the old stuff out than I did installing the new unit and wiring. So I have technically a 2 wire Alt, but it is a one wire charging system with a monitor wire.. I get 13.8 volts most of the time, except when all of the electrical is running, then it drops to 13.5 volts...

So Yes you can have a one wire with the idiot light

Tuff Stuff Performance 7068 - Tuff Stuff One-Wire Alternators - Overview - SummitRacing.com

 

To correct my previous post, it would be much better to run a #8 from the alt. output post to battery +, but please use fusible link wire for safety. If you can't find fuse link thick enough you can always double it up where it goes onto the starter relay. There's always only one charge wire. Even if the 2nd wire is just a trigger.

 

Yesterday over lunch I picked up this alternator, a Delco-Remy 7127-1WA. (EDIT: that is the Carquest part number. this is also known as the Delco-Remy 10-SI alternator.) After reading the last few posts I’m thinking I probably want to go with a 3-wire. A little extra wiring does not bother me. But jetcopterpilots’s post is interesting. I notice that this alternator has a rubber boot covering a small terminal post- might this be an idiot light terminal???

 

3-wire > 1-wire.
Catalog

there's nothing wrong with the Delco 10SI/12SI units, but this seems like a perfect place for a Ford 3G installation.

 

That would be the case! there should be two terminals under the rubber boot. the number one terminal was the idiot light terminal on the Tuff Stuff Alt should be the same on that one too. Don't see any reason that it should be different. I would assume they are all standardized.

 

Yep, I called Delco-Remy support line to confirm this. The guy was very helpful and also emailed me the technical bulletins on this alternator. I guess I'll dive into this tonight!

Update: This install is complete. I had to lengthen the top bracket to get enough tension on the belt. That plus a couple of washers and it lines up and works great.

No luck getting the idiot light working so far. I have one more thing to try and if that doesn't work I will get an aftermarket low voltage sensor made by Ron Williams for this purpose: http://www.ronfrancis.com/products.asp?dept=300

 

I was thinking the same thing.