need help fixin' vehicle

[rockinmywaypa]

My son has a 98 dodge dakota, recently it stopped charging and he barely made it home in the partial darkness. I checked the difference between battery voltages when shut off and when running and lo and behold it was charging again. He drives it to school and halfway there it stops charging. Back home and testing and it starts charging again. Right now I'm not sure what to start replacing, hopefully it's not the wiring which could be a real pain tracking but what would be the order of cheapest probable cause to most expensive hopefully last resort to change. Thanks for any help.

 

[JDgreen227]

My son has a 98 dodge dakota, recently it stopped charging and he barely made it home in the partial darkness. I checked the difference between battery voltages when shut off and when running and lo and behold it was charging again. He drives it to school and halfway there it stops charging. Back home and testing and it starts charging again. Right now I'm not sure what to start replacing, hopefully it's not the wiring which could be a real pain tracking but what would be the order of cheapest probable cause to most expensive hopefully last resort to change. Thanks for any help.

How old is the battery? Are the terminals clean and tight? Is the negative ground on the frame clean and tight? Are the connections on the alternator clean and tight? Is the alternator belt in good shape, or loose and slipping? Most charging problems are caused by these simple reasons, if these don't pan out check the voltage regulator...not sure if it is built into the alternator or not. May be a failing alternator...and just curious, how far is the commute to school? How far does the truck go before it acts up? Hope this helps.

 

[LD1]

Not saying it cant happen, BUT I have NEVER seen an alternator charge and then quit and then charge again. It either works or it dont. So It doesnt sound like that is the issue to me.

I would start by assuring that ALL the batter and alternator connections are tight AND clean. Also make sure the belt that drives the alternator is tight as well.

Given the information you supplied us with, My money is on it being a loose/corroded connection somewhere.

 

[JDgreen227]

My dad had a starting/charging problem on his '77 F100, it drove him nuts...and it was a poor connection on the negative cable where it connected to the frame...loose and corroded.

 

[rockinmywaypa]

You guys are quick, The connections on the battery are clean and tight, I don't know the age of the battery but it holds up for however long the truck is parked, sometimes a couple weeks this winter and still started right up despite Canadian low temperatures. The belt looks decent and is tightened with a spring loaded idler on a serpentine belt so I can't tighten it any more. I think the regulator is built into the alternator, There is fuse or solinoid or relay thingy near the fuse box that has a cloudy look but looks ok inside the glass case. The school commute is about ten miles or a fifteen minute drive whereas he got about halfway there when he noticed that the red light was on on the dash to let him know it wasn't charging. I will definetly check out the neg. cable to the frame and maybe remove it to make sure it hasn't built up with rust between the layers.

 

[JDgreen227]

You guys are quick, The connections on the battery are clean and tight, I don't know the age of the battery but it holds up for however long the truck is parked, sometimes a couple weeks this winter and still started right up despite Canadian low temperatures. The belt looks decent and is tightened with a spring loaded idler on a serpentine belt so I can't tighten it any more. I think the regulator is built into the alternator, There is fuse or solinoid or relay thingy near the fuse box that has a cloudy look but looks ok inside the glass case. The school commute is about ten miles or a fifteen minute drive whereas he got about halfway there when he noticed that the red light was on on the dash to let him know it wasn't charging. I will definetly check out the neg. cable to the frame and maybe remove it to make sure it hasn't built up with rust between the layers.

Shoot, there go most of our easy fix solutions....

 

[Mace Canute]

Very high mileage? Check internal brushes.

X 2! :thumbsup:

 

[LD1]

Well if you are sure all the connections are clean and tight, including the ground to the frame that you said you would check on...

...And if you are sure the battery is good (which it sounds like)

...And if it has an internal regulator in the alternator

...Just spend the $100 or so and replace the alternator. That is the only thing it can be at this time other than a faulty guage or sending wire to the guage. It could be that it is charging just fine but a loose connection to the guage could cause these problems.

But I'd probabally start with the alternator. Especially if higher mileage, given that it is almost 15 years old.

 

[JDgreen227]

"Sending wire to the gauge"...from what I interpret the truck has a warning light not a real ammeter. I hate working on vehicles that don't have real gauges just stupid idiot lights. An ammeter gauge would likely tell if things were charging or not.

 

[Lil_FarmerJim]

+1 for what LD1 said. If the regulator is internal to the alternator, then just replace the unit. Depending on your local auto parts store, some offer free diagnostics if you bring the thing into them. So you could just pull it out take it to the store and have them test it. That way you don't waste the money on a new one.

But I would be leaning towards just replacing it do to its age and mileage.