Battery won't hold a charge
 

I just bought a 91 dodge dakota v8 318. The battery wont hold a charge in it. It has the check engine light on when truck is running. Battery is also drained while engine is running. What could be wrong? I got error code 41 which is Generator field not switching properly. What should I look at?

RE: Battery won't hold a charge
 

I am guessing that it has something to do with the alternator.
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RE: Battery won't hold a charge
 

As jonnymangum said, its something to do with the alternator.
Here is a wirng diagram. Let us know what you find.

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RE: Battery won't hold a charge
 

Yeah....what they said.

I would look at the wiring around the alternator, check for chaffing, bare wire, cracks in the insulation. Also look for corrosion on the connections. I would check the wires around the battery also since they go to the alternator. If they all look fine......I would replace the alternator. At least check it out with a multi-meter. You definitly have a short somewhere.

Another thing to look into would be have you or anyone else hooked anything electronic up lately. If so check the wiring on that.

RE: Battery won't hold a charge
 

Well replaced the alternator today. No change did a little probing around with the meter and found out its starting to look like the previous owner fried the ecm. How much would a new ecm run for this truck due to i just got this truck and kinda got a tight budget? thanks again for the help

RE: Battery won't hold a charge
 

I have one that I wouldnt mind letting go. It's for a 94 engine though so I am not sure if it will jive with a 91. Chances are if you have multi port injection it may work, but from what I understand they didnt do mpi till 92. I am positive the computer is fine. I bought a new one during a 2 month ordeal of a mysterious problem my truck had and two mechanics told me it was either one of the sensors or the computer.

Well after alot of swapping, replacing, time, and money....I found out it was the combination of a worn out timing chain and a deffective distributor cap that I had bought brand new. Now the ol kota runs like a champ again. Better then when I bought it acctually considering everything is brand new from the computer to every sensor on the thing, yet I still saved alot of the parts I replaced except for the ones I knew were shot.

RE: Battery won't hold a charge
 

i doubt it will fit mine due to i dont have mpi. check the sticker on it tho and there should be a big number made like in bold type. what is is? if that number were to match mine them it will work. thanks

RE: Battery won't hold a charge
 

The big number on it is a 8749.

RE: Battery won't hold a charge
 

thanks anways that one wont work in it i need a 924 which i have had a hard time finding and still have yet to find one at a salvage yard.

RE: Battery won't hold a charge
 

Where do you live???

I know of a junkyard along route 54 outside of turbotville pa. They have a couple trucks with the computers I believe you would be looking for. I know they are throttle body injected 3.9's. When I was there a couple weeks ago, the trucks were more or less complete. One was a rollover and the other looked fine. I was amazed it was there.

Another thing to do would be to look on ebay. There are alot of parts on there to be had.