Before I drop $220 + shipping on a DB 160 amp alternator, I want to make sure I'm not overlooking anything.

I was stranded late Christmas Eve (32 degrees here) with dead batteries. I finally got truck jumped and drove it for 3 hours to the in-laws' house. Started it once each day for the next 3 days and it started without issue, but the day we were headed home it had to be jumped again. Both batteries were at 11.8V when I got home, so I got two new 1000CA / 850CCA batteries and put them in. Weather got near freezing again and truck wouldn't start today.

Batteries were at 11.5V. Put the charger on for a bit and got it running. After the GPR turned off, I checked voltage at the batteries and it was 11.9V. Output on the alternator was also at 11.9V. Got the wife to hold it at 2000 RPM, alternator was 13.5V. At 3000 RPM, alternator output was 14.4V. Assuming the voltage regulator is bad based on that. I check the 2 small wires on the alternator, the orange was 11.7V (same as battery as the GPR was still on) and the yellow was 11.2V. I had read a few threads of people saying the orange wire had an issue and prevented the alternator from "exciting."

Anything else to check before ordering a new alternator? The wife will not be happy if I spend $500 on an alternator and 2 batteries and it still has issues!

Thanks,
-Chris

 

get a new wife.

 

Hope you don't mind "Made in China" with the DB.

 

Are you positive those new batteries are fully charged when you are testing voltage?
If they are deep discharged they will suck down the voltage pretty hard until they get charged all the way up.
.
As far as the drain is concerned it could be a bleeding diode, or a leak through the stereo, or any other possibility.
Need to find where the power is bleeding off.

 

j/k lol


you can take truck to any auto parts store and check the alt while on the truck. idle voltage output is one parameter they check

 

The alternator field winding is supplied current thorugh a fuse.

Be sure it isn't blown, first.

Pop

 

I've got them on a 2 amp trickle charge tonight. but if the alternator is only putting out 11.9V at idle, would not-fully-charged batteries cause that? My thought process was that the alternator wasn't able to keep them fully charged and the 24 hours of 32* temps was too much for them to handle. And since the alternator wasn't always able to put out 14+V, the batteries never got fully recharged during normal driving. I'm guessing I could charge the old batteries and they might still be good.

Thanks for the input on DB, is the china reference a knock on their quality or a knock on them not being made in America? If it's the first, does anybody have any good experiences with other manufacturers that are priced competetively? If it's the latter, does anybody have any good brands that are made in America?

-Chris

 

There is a fuse that will not allow the Al to charge if blown... Check the under hood fuses.


Edit... You have a 2003... its under the steering column...

 

Funny - that's what my wife said when I told her about the problem!

 

Which fuse is this? One in the fuse box by the driver's kick panel or somewhere under the hood? FYI, it's an '03.

-Chris

 

'03, no fuses under hood. all fuses under driver side dash.

 

See the owner's manual in the glove box. There's a fuse chart in there that tells you what they're for, and where they're located.

Pop

 

I have bought starters and alternaters (3 starters-3 Alternators) from DB for several years with no problems

 

I 2A trickle charged the batteries to a full charge and also took apart all of the battery connections and cleaned them. That got me an extra .5V while running, but that's still only 12.3V at idle from the alternator.

Pop - do you by chance know which fuse supplies current for the alternator field winding? I didn't find any blown fuses, but some of the fuses I didn't check b/c the description in the owner's manual seemed like it would not affect the alternator in any way.

I'm beginning to think it's time to pony up the $250 for a new alternator....

Thanks,
-Chris

 

Chris,

I got a little surprise when I looked up the 2003 7.3's charging system. It looks like they have eliminated the fuse for the field windings. See:
http://www.e-toolbox.com/ads/wiring/va169323.pdf

I looked at the Owner's Manual PDF to be sure......
http://www.motorcraftservice.com/pub.../03f23og5e.pdf

It's not in there! Whooda' thunkit?

Pop