Voltage Regulator

[Tumbler]

Need some help finding the voltage regulator.



Bought the truck in March. Problems have arisen sooner than I thought. Though I do have TDR membership, I do not have the right resources yet... to find my way around the truck.



Thanks in advance!

 

[Greenleaf]

It be an integral component of the PCM mounted next to the battery.

 

[Tumbler]

Thanks.



I'll start from the beginning.



Truck didn't start one morning. Got it jumped. Battery checked out fine at Sears. Also plenty of water in it. Noticed later that the voltmeter was positive over the charge of the battery, so assumed that the alternater was working fine.



Also noticed that the battery would lose a noticable amount of its charge overnight but would carry a normal charge following operation. I'd check by turning key but not firing up the truck and after shutting the truck down, I'd turn the key but not fire it up again.



Noticed recently, either this week or last week that the battery was not charging and was slowly losing its charge through use.



Got the alternator tested with Napa. Checked out fine. Napa sold me a voltage regulator for the truck. I did verify that it was for a 92 Dodge 5. 9 Cummins before purchasing. Can't return it now.



Any clue as to what happened?



Can the voltage regulator go bad without affecting the rest of the PCM? What would cause the voltage regulator to go bad?



Thanks again!

 

[Tumbler]

Found this article. Will continue to search for answers.



http://www.dieseltruckresource.com/...q&nr=161&catnr=20&prog=1&lang=en&onlynewfaq=1

 

[matches]

Greenleaf, I'm probably mistaken, but I thought the voltage regulator was mounted just off center to the passenger side,on the fire wall, just below the hood?

 

[Tumbler]

What does it look like? I've included a link to a regulator simiar to the one I bought. I could not find triangular jacks that would fit. I also couldn't find anything that looked similar to the voltage regulator I bought...



http://www.partsamerica.com/ProductDetail.aspx?mfrcode=NIE&mfrpartnumber=AL154&parttype=204&ptset=A



I did find three drill holes on the left wheelwell near the battery that was somewhat similar to the pattern of the voltage regulator... but it wasn't a perfect fit.

 

[HRDROKN]

Any clue as to what happened?

Did you check the Auto shutdown (alternator) relay?

 

[Tumbler]

Sorry, I'm not sure what that is.

 

[matches]

Thats the one, mine is located like I said on the firewall, just off from center.

If I remeber correctly it has one blue and one black wire on the plug.

 

[Tumbler]

Found the following. Do you know which one I would test and how to go about testing? I saw about three box shaped relays under the hood and one cylinder relay under the dash.



http://www.partsamerica.com/ProductList.aspx?PartType=844&PTSet=A&SearchFor=Miscellaneous Relay



http://autorepair.about.com/library/images/bl763lib.htm



http://www.partsamerica.com/SearchResults.aspx?Keywords=ASD+relay

 

[Tumbler]

Thanks Matches. It sounds like it would be easy to find... I seriously went over the truck for hours trying to find plugs and parts that match.

 

[HRDROKN]

Sorry, I'm not sure what that is.

On the drivers side fender there are three relays... A/C clutch, starter and ASD relay. I can't look at the truck right now to tell ya which one is which, but if I remember correctly it is the one with the same color wires as those that go to the alt.

 

[Tumbler]

blue and black? I'd test it by replacing the unit?

 

[HRDROKN]

blue and black? I'd test it by replacing the unit?

Looking at the ASD schematic and with the relay in hand... hook up 12V power to the coil side and listen for a click.

 

[Tumbler]

Thanks! I'll look into it.

 

[HRDROKN]

OK... I went out to the truck. The ASD relay is the one with the green/orange wires.



To test... disconnect relay and you will notice that the spades a numbered. Hook up 12V to spade 85 and a ground to 86, you should here and feel a click if it is good. Now with that said it could click and have bad contacts, so to test further run an ohm meter across spades 30 and 87 reading should be infinite.



Hope that helps... .

 

[Tumbler]

Thanks, I'll check it as soon as I can!

 

[Moab4x4]

Those are a generic automotive 12V relay and are available many places. You should even be able to test them by swapping the start relay for the ASD relay and see if the truck starts.

I am not sure why they changed from the old design with the intercooled trucks, but I changed mine back to the old style regulator and it worked great.

What you need to happen is to get voltage to the field post on the alternator. There are the two small posts for field. The voltage across those posts controls the amount of charge from the alternator. An old Mopar manual recommended an alternator test of just putting one post to ground and the other to 12V and see if you charge. I made it home on a trip once by using a jumper wire to that post from the battery for a little while from time to time to recharge the battery at max and then drive while it slowly discharged. @ each rest stop we jumpered the field wiring to recharge the battery for a few minutes. Don't leave it jumpered too long or you will cook battery or alternator or both. Just look in any old Mopar manual to see how to wire the regulator. My 73 Dodge used the same regulator.

Ken

 

[dpuckett]

FWIW, they went to integral voltage regulators in the PCM in 92. I make a habit of having part number in hand when I go to the parts stores. (most ask for with or without intercooler for ALL 1st Gens, not just 91).



Are you seeing the volt gauge all over the scale, or just low? If it is low, I'd cehck elsewhere, though it could be the PCM. I had a 93 that went haywire at midnight in central MO. I pulled over and slept til daylight just to keep frmo flashing my lights at other drivers. It literally went from about 9 to 16volts. I had it bypassed and a traditional volt regulator installed. Had a constant check engine light, but a small price to pay.



Daniel

 

[Tumbler]

Thanks for all the input guys. I have not had a chance to check into whether the Voltage Regulator/PCM or the relay is the problem. Busy weekend.



I also found that if one or more of the following (Tachometer, Cruise Control, Air Conditioning) is out then there could be a problem with the crankshaft sensor... which also affects battery charging. True?