Mopar help needed

W

wmmalett

New member
Calling all Moparites......


I have a 2000 Dodge Dakota 3.9 V-6. I was driving home from work the other day and the "Check Gages" light came on. I look to see
what's going on and the voltmeter is down to 8 volts(the same spot where it is when the truck is off. So I take it to Advance Auto Parts so they can check the alternator,on the truck. Their diagnosis, the alternator is not outputting what it should. So I have them get me one $150.00 later and I put it on. Problem solved. Nope. I was taking the core back to the auto
parts and same thing happened. This time they check the battery and the machine said that the battery was good but it had a low charge. They couldn't test my old alternator but Murrays could and come to find out
my old alternator is just fine. I got to nosing around under the hood and I noticed the cover for the other set of fuses on the truck. Great!!! There's a 50 amp fuse for the alternator and it's blown. Problem solved. Nope. Went to go to work this morning and got about 2 miles down the road and same thing as before, check engine light and 8 volts on the gage. Called the
dealer today thinking there might be a voltage regulator that could be replaced and there isn't. According to the dealer the only problem could be the alternator, fuse, or the PCM( at a cost of $600). Has anyone out there ran into this problem on a Dodge??? If so was it the PCM or am I missing something else??

Please help!!!!

Thanks,

Bill
 
Sounds like a PCM problem. the field voltage is controlled by the PCM.


wmmalett said:
Calling all Moparites......


I have a 2000 Dodge Dakota 3.9 V-6. I was driving home from work the other day and the "Check Gages" light came on. I look to see
what's going on and the voltmeter is down to 8 volts(the same spot where it is when the truck is off. So I take it to Advance Auto Parts so they can check the alternator,on the truck. Their diagnosis, the alternator is not outputting what it should. So I have them get me one $150.00 later and I put it on. Problem solved. Nope. I was taking the core back to the auto
parts and same thing happened. This time they check the battery and the machine said that the battery was good but it had a low charge. They couldn't test my old alternator but Murrays could and come to find out
my old alternator is just fine. I got to nosing around under the hood and I noticed the cover for the other set of fuses on the truck. Great!!! There's a 50 amp fuse for the alternator and it's blown. Problem solved. Nope. Went to go to work this morning and got about 2 miles down the road and same thing as before, check engine light and 8 volts on the gage. Called the
dealer today thinking there might be a voltage regulator that could be replaced and there isn't. According to the dealer the only problem could be the alternator, fuse, or the PCM( at a cost of $600). Has anyone out there ran into this problem on a Dodge??? If so was it the PCM or am I missing something else??

Please help!!!!

Thanks,

Bill
Click to expand...
 
That's not what I wanted to hear. Does anyone have one of these things?? Or know of a junk yard that I could get one?
 
wmmalett said:
That's not what I wanted to hear. Does anyone have one of these things?? Or know of a junk yard that I could get one?
Click to expand...

i've been going to a junkyard off rawsonville road and 94 called RT's. they have a huge field of cars and can get just about anything you need. 7344857676. they know who i am because of all the crap i've bought there, lol.
 
i think its kinda common but for 10 bux you can convert it to external regulator and be done. (grab one from a 80ish ramcharger) just get the connector from a junkyard one or use butt connectors to fit over the terminals.

Ps also check grounding to the alternator or add one for security.
 
MystryGuy said:
i think its kinda common but for 10 bux you can convert it to external regulator and be done. (grab one from a 80ish ramcharger) just get the connector from a junkyard one or use butt connectors to fit over the terminals.

Ps also check grounding to the alternator or add one for security.
Click to expand...
been there, done that
 
This sounds like a great fix. A hell of a lot cheaper too. But exactly how would this wire in to the existing system? As for grounding the alternator wouldn't it be naturally grounded being that it's bolted to a bracket that's bolted to the block and the block is where the ground wire goes from the battery.

Thanks,

Bill
 
you'd think it'd be grounded but corrosion and paint can cause a weak ground. I tested mine when i had that problem and it had alot of resistance. Wiring for external reg here: http://www.dieseltruckresource.com/pics/data/500/17307regulator21.jpg
http://www.dieseltruckresource.com/...q&nr=161&catnr=20&prog=1&lang=en&onlynewfaq=1
I went thru and sanded every ground mounting point on the harness because i couldnt find my problem then find the damn alt. wasnt grounded well, doh! 2 weeks wasted of f-n around...
 
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Thanks for the info. The pic shows 2 alternator terminals and I only have one unless it's counting the connector that's on the back of the alternator. It has 2 wires coming out of it. I'm assuming that one wire is for the volt meter not sure what the other one is for and I know the thicker wire is going to the battery.

Thanks,

Bill
 
wmmalett said:
Thanks for the info. The pic shows 2 alternator terminals and I only have one unless it's counting the connector that's on the back of the alternator. It has 2 wires coming out of it. I'm assuming that one wire is for the volt meter not sure what the other one is for and I know the thicker wire is going to the battery.

Thanks,

Bill
Click to expand...

those are the two wires, leave the big one to the battery, IIRC, the green wire to the plug on the alt is the output from the ASD relay, so you should be able to use that to power the regulator
 
O.k. I didn't try the external voltage regulator yet. But I did pick up another PCM and put it on and replaced the 50 amp fuseable link for the alternator and the same problem arises. It gets up to the normal 14 volts on the gage at idle, then when I bump the rpms up to about 2000 and hold it there the volt gage begins to drop. Shut the engine off and look at the fuseable link and it's blown, again. Anybody have any idea why this fuseable link keeps blowing?? The alternator is fine, the battery is fine, and by installing another PCM I'm pretty sure that's not the problem. HELP!!!!

Thanks,

Bill
 
loss of electrons

wmmalett said:
then when I bump the rpms, the fuseable link and it's blown, again. Anybody have any idea why this fuseable link keeps blowing??

Bill
Click to expand...

Bill, something has to be sucking all that current when you raise the RPM for the fuse link to blow. Do you have any extra stuff (amps, etc...) that could be shorting somewhere, that possibly are NOT fused? The fuse links pretty much are there just for direct short conditions.

Steve

Oh, I work at Chrysler in case you need more info.
 
Last edited:
Steve,

No extra stuff on the truck. It's all stock. I haven't done anything to it. It's strange too because the trouble began driving down the expressway. I'm assuming that's when the fuse first blew. Is it possible that the battery finally went, it's the original to the truck 7 yrs old now, and it's causing the fuse to blow? Any help would be greatly appreciated.

Thanks,

Bill
 
checked manual

Bill,

I looked at the schematic for this. It shows a 140 amp fuse link, not the 50 you mentioned. I also talked to an alternator guy. The fuse link actually is there in case a diode in the alternator shorts. That would short the battery direct to ground. The fuse link protects the battery and wiring when the diode goes.

So, without seeing the truck. Look to make sure the fuse link is indeed a 140 amp fuse link. And, the alternator positive post is not somehow shorting to the engine block or something strange like that.

PM me if this is still an issue. I'll send you my direct email address. I don't check this board often enough. The PM will send an alert to my email.

Steve
 
check and make sure the charging output wire didn't melt its insulation and create a ground path.

post above is correct the fl is 140 not 50


wmmalett said:
Steve,

No extra stuff on the truck. It's all stock. I haven't done anything to it. It's strange too because the trouble began driving down the expressway. I'm assuming that's when the fuse first blew. Is it possible that the battery finally went, it's the original to the truck 7 yrs old now, and it's causing the fuse to blow? Any help would be greatly appreciated.

Thanks,

Bill
Click to expand...
 
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