Hello folks,

My Bee-Mobile is my '91 Dakota (5.2 v8).

A month or so back, I would occasionally get the CEL with code 41 - but now - it's on pretty much on all the time.

Last weekend, I made a 4-hour trip in the truck, and when I got home, I noticed that the voltage gauge showed pretty low (~10v) and when the blinkers were on, the gauge would drop lower. Once I stopped the truck - the battery was drained. Had to jump it off another car to start back up.

After charging the battery for about 24 hour - took the battery to 2 places to have tested, checked out fine at both, and AutoZone says that the voltage (at 12.2 with engine running) is low. Also mentioned that if the truck is running, and I were to disconnect the ground wire, that if the truck still runs, then alternator (or charging system) is probably okay.

Well, I went ahead & replaced the alternator with a new one - and V is still at 12.2v. CEL is still triggering.

My question(s): There is a wiring harness/box bolted to 2 small bolts near the top of the alternator - what does this packet of wires/box do? Could there be something inside that is bad?

http://www.teesandthings.com/art/AltHarness.jpg

Where is the voltage regulator? Is it in the alternator, or on the firewall as mentioned in the Haynes manual? (Is this pic the connector to it on the firewall?)

http://www.teesandthings.com/art/VReg.jpg

There is also a harness next to this one that is just hanging loose. (See linked pic) Any idea what this one is for?

http://www.teesandthings.com/art/harness.jpg

Where do I need to start looking for a solution to the dying (non-charging) of the battery?

(I tried disconnecting the battery while engine was running - and it immediately died. When I restarted it ran a little rough for a minute, then smoothed back out)

Thanks folks!
Rex S,

 

http://www.justanswer.com/dodge/6hos...-charging.html

good info on testing PCM circuit(which trigger alternator to charge) the regulator is built into the computer itself

First pic is typical :O cant remeber the name for it but it has gren wire(which triggers the charging circuit) lol

that second picture is heater blower motor fan resistor pack(high med low)

third pic is OBD1 data connection port for diagnostics

 

Now that looks like a small project! I may try to find a replacement PCM before shooting to retro-fit with an external voltage regulator. Looks like on a quick search that a replacement computer for the Dakota runs in the $160-$200 range - and would keep the CEL off when working properly, where teh external regulator would always have the CEL triggered.

Luckily I have another vehicle to use for a bit.

Thank you for the identify on the other harnesses!

Rex

 

well u can always try grounding the green wire to see if it charges... if so you know its the pcm ... regulator is easy to setup and is hella cheaper too but test out grounding the wire first..

 

The green wire that goes to the pack on the alternator, right?

Will do - If I can find a bared section of wire - or should I just use a sharp test-probe into the green wire and ground it out that way?

 

yea anywere on that wire that goes to alternator, this is a grounding trigger wire the PCM uses to charge. probe would work good just dont stab yourself lol (been there done that)

 

With green wire grounded - the voltage popped up to 14.3v. Nice.

 

now you can check wiring make sure its not damaged all the way back to pcm..

then you can go cheap way and setup external voltage regulator... fairly simple to be honest..

or spend some cash and replace PCM

 

I understand and appreciate that the external regulator is probably MUCH cheaper (or less expensive) - and I'm fairly proficient with electronics - and you can't get much more frugal than a beekeeper (lol)...

My aversion to doing it, though, is for future repairs - and peace of mind of having the CEL stay off (for this reason). If it's always on - I'll become complacent, and never check occasionally to see if it has thrown any additional codes...

I checked continuity from my test point at the alternator - back to the harness (pin 20) - and continuity is good - so PCM is the culprit, I suppose.

Thanks again!!!

 

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