Hi all,

I've been researching this on this forum and haven't found a good answer so I thought I would ask for your opinion.

I have a '96 XL with 5.8. The stock alternator was very noisy (bearings going bad?) so I went to the AutoZone and bought a new 95 amp alternator (Duralast). The new one is much quieter but at idle with the heater on, headlights, radio, etc the interior lights dim and I can tell that the blower slows down. As soon as I hit the gas it picks back up. The voltmeter shows the corresponding drop in voltage (but it still barely reads in the normal range). From searching this forum this sounds like a common problem for Broncos. I never had this problem with the old alternator so obviously my concern is that I got a low output alternator. I should have written down the part number and information from the Motorcraft alternator but I didn't do that before I turned it in as a core.

In response to the problem, I cleaned the battery terminals to see if that might help but it didn't. I will also take the battery and alternator to be tested but my bet is the local parts house will test them and say they are good. That means I either live with this problem or get a new high output alt.

I just recently got a service manual and it states that the stock alternator was 130 amp (I did not know this when I bought my new 95 amp). Most of the research I've done on this subject relates to people doing the "3g" 130 amp swap.

I guess my main questions are:

1. Did the 5.8 Broncos originally come with a 130 amp alternator?
2. If so, why do the parts houses only sell 95 amp alternators (or might the 95 amp version be for the 5.0)?
3. Are 130 amp alternators still available through Ford if I elect to not do the 3g conversion using a mid 90's Mustang alt?

I have gained a ton of knowledge from reading this forum. Thanks to everyone for all the great posts. Luckily I haven't had the tailgate problem (yet) so I'm sure I'll be reading all about that once my rear window dies!

Regards,

Marshall
Lexington, KY

 

being a 95, your alt. should be a 3G already. You can tell the difference by looking at the case size, the 130A. one will be bigger around than the 95A. I'm not sure what size came stock on your truck because ford put both sizes on the f-150s and maybe bronco, due too different options.
You idle may be low, casue with everything on it should not be more than 50-60 Amps.

Just too make sure you have a 3G, does your alt. have one plug for the regulater, one sigle wire plug for sence and a stud and eyelet going to the starter solinoid?
If your alt. has 2 big plugs with 3 wires each and that it, then thats the flamin 2G

 

96 Broncos typically came with a 95 (2G) amp alternator. You do not have to do any fancy conversion, as many OEM manufacturers make a higher amp alternator for this application. You just have to find a parts shop that has the desire to look beyond the friggin computer screen.
My parts guy called the company they buy their alternators from. Lo and behold, they had a 150amp high output alternator for my application. I got it the next day and bolted it in with no alterations or adjustments required. Plugged in the two plugs and away I went. No more dim lights at idle, more than enough power for anything I want to do.
I cannot remember what the manufacturers name is, but I bought it through Autoparts International (Northeast US). I have the receipt in front of me, no part number as such, but KeyNo is N3488 and Reference No is 7768. I paid $150 for it and it was worth every penney.

Hope this helps.

 

I would'nt trust that many amps going through the plug, if they can melt and burn just with 95amps.

 

According to Ford (checked before I bought the alternator) the factory plugs for the alternator are factory certified to handle up to 200amps.
I purchased my 150 amp alternator in September of 2002. No discoloration of plugs, wires have not discolored or hardened. Not one sign of any ill effect from the higher output alternator.

 

Thanks for the input.

I agree... my idle might be low (I haven't hooked up a tach) but the old alternator didn't have this problem. So idle rpm might be part of it but it's not the primary reason the lights dim at idle.

I do have a 3g alternator based on BroncoRoadKill's description. I have a 3 wire plug, a 1 wire plug, and then a thicker gage wire on the stud. It is listed as a "7750" which I believe translates into a 3g series alternator with 95 amp output.

So I would assume I could go get a 130 amp 3g alternator intended for a 94-96 Mustang and it would bolt right up. Any thing to watch out for?

Marshall

 

Should all be plug and play.
Just inspect the plugs for any possible problems.

 

Hi all...

Just to give a final conclusion on the problem...

I went to the part store and the '95-'96 Mustang 130 amp alternator that they had would not fit. I had the original alt with me so I knew it was not a "plug and plug" solution.

We put the 95 amp alternator that I bought on their test machine and it tested bad (output ~ 10 volts). Apparently that alternator that I bought new was defective. They exchanged it with an identical unit (95 amp, Duralast DLG7750) and we tested it and it looked good. I put it on the truck and no more problems with dim lights or slow blower motor.

Thanks all for your input. I appreciated the help.

Marshall