Alternator or.......?

Atsah · Jun 24, 2012

I had this problem on at least a couple of trucks and each time, I had a bad ground strap..

Snake · Jun 24, 2012

Funny you should say that......I haven't checked those yet, mainly due to the weather (take a look at what's been happening in FL LOL )

If that's all it turns out to be, I'm sure I'll have some mixed emotions: relief at finding the problem, and remorse for buying a new alternator if the old one was still good. LOL

mortal798 · Jun 24, 2012

A lot of times when people hang an alternator for a problem like this, they find out later that it's a wiring concern. Test everything first. Just because there's no output doesn't mean the alternator is bad, the regulator control circuits(s) could be the culprit. All you need is a wiring diagram and a DVOM. I'd rather fix a wire than replace a $200+ dollar part.

mortal798 · Jun 24, 2012

If you are only getting 11.47v and 12.0v, you probably have corrosion somewhere in those two circuits. You should have within .1v of battery voltage, and if your B+ voltage is 12.3v, you are losing it somewhere. You need to find where.

Snake · Jun 25, 2012

Just dropped the truck of at the local shop........hopefully it's something simple

Diezel Dawg · Jun 25, 2012

How bright is that battery indicator light compared to all you other cluster lights? If it is not as bright, change it out. My truck was doing the same thing. Took it to an auto electrical shop, and they found that bulb not as bright as.it should be, and replaced it, fixed the problem. The light bulb fees the alternator and.excites it

Sent from my EVO 3D on the East Side

Snake · Jun 26, 2012

It's the same brightness as the rest of the lights.

On a side note, I saw something interesting driving to the shop yesterday. At idle, I'm only getting 12.2 - 12.6v, which is just enough to keep the battery light from coming on. Once I build some rpms I'll get 13.0 - 13.5v. Not where it should be, but it indicates that the alternator is at least doing something.

More to come....

Snake · Jun 26, 2012

The shop double checked my troubleshooting and load tested the batteries. Everything looks good except for the alternator. At idle, it's under 12v with the A/C on, but will increase to just over 13v with engine rpms.

They also checked the alternator output, but I forgot to ask them the numbers. Bottom line is that it wasn't where it should be.

Looks like I have to pull the new alternator, ship it back to DB, let them troubleshoot and likely replace the alternator, and wait for a working alternator to be returned to me. It'll probably be a week or slightly more before I'm back up and running again, but at least I don't have to pay to ship the alternator back.

I'll post updates as they're available.

And I'm not real happy about losing my truck for another week.

Snake · Jun 29, 2012

After thinking about it another day, I decided that I didn't want another alternator from DB Electrical. Right after FedEx picked up the package, I called DB and let them know I wanted a refund instead of another alternator. To be fair, every person I've spoken with at DB has been professional and courteous, and they didn't give me a hard time about the refund.

Soooo, now what? How about a 300a alternator from DCPower? :rockon:

https://www.dcpowerinc.com/fit/2005...~6.0L-V8-Powerstroke-Diesel/8307-300-spx.html

Should be here Tuesday.

Oh, and DC Power is having a BIG 4th of July sale next week.

mortal798 · Jun 29, 2012

Post an update after you install it, I hope it fixes it because chasing wires isn't a whole lot of fun.

fat-fingered from my EPIC 4G

Snake · Jun 30, 2012

I'm officially ***in baffled. I borrowed an OEM alternator from a friend today, and had it bench tested before I installed it. Tested good on the bench, slapped it on the truck, and I'm seeing 12.3v at idle, bumping up 12.6v at 1500 rpm (as read off the back of the alternator with a multimeter). Everything off at that point: no A/C, no stereo, GP's finished their cycle, etc......

Double checked my voltage drop across the alternator to battery wire and read 0.17v .

Truck is real close to being parked in a public lot with a "No Lojack, no GPS, no alarm, key in the ignition. This is not a bait car" sign in the windshield.

bad moose · Jun 30, 2012

I hate to say this but have you searched the "Nation" ? I want to say about two years ago there was a guy having the same issues. I can't remember what he did to resolve it though.

Snake · Jun 30, 2012

I hear ya, and I searched even though the site is going down faster than a fat chick on a President. Couldn't find what I need there or on the org.

Atsah · Jun 30, 2012

Snake said:
I'm officially ***in baffled. I borrowed an OEM alternator from a friend today, and had it bench tested before I installed it. Tested good on the bench, slapped it on the truck, and I'm seeing 12.3v at idle, bumping up 12.6v at 1500 rpm (as read off the back of the alternator with a multimeter). Everything off at that point: no A/C, no stereo, GP's finished their cycle, etc......

Double checked my voltage drop across the alternator to battery wire and read 0.17v .

Truck is real close to being parked in a public lot with a "No Lojack, no GPS, no alarm, key in the ignition. This is not a bait car" sign in the windshield.

It's a 6.0, no one will take it LOL..

bad moose · Jun 30, 2012

http://powerstrokenation.com/forums/showthread.php?t=55690&highlight=electrical

Not the thread I was thinking about. But something the to look at. I forgot about the second one.

Yeah, I haven't been over there since this site started. Was a little at first, then it was just getting stupid so I stopped. It's too bad we have to watch it go down in flames.

Snake · Jun 30, 2012

The only thing I can think of at this point is a bad ground. Will be checking all of them again tomorrow.

Mark - I bet I'd have a claim to file if I did that in TX. LOL

Atsah · Jun 30, 2012

Mike I would think you have a bad ground or cable somewhere.. Is your tensioner pully working okay?

I had to cut the wire coming off the alternator that goes back thru the instrument cluster to the idiot light and ran it straight to the fuse in the fuse box under the dash and I didn't have any trouble since on one of my trucks..

Snake · Jul 1, 2012

Thanks Mark. Tensioner pulley looks good to go. No signs of slipping, squealing, or belt wear.

2wd-fire · Jul 1, 2012

my buddy glow plug module went bad and had simalar problem would start up and drive fine but only read 12v also fried his alt un plug it and see what happens only take 2 mins jmo

Atsah · Jul 1, 2012

2wd-fire said:
my buddy glow plug module went bad and had simalar problem would start up and drive fine but only read 12v also fried his alt un plug it and see what happens only take 2 mins jmo

I have heard of that happening as well..