'92 with no charge from the alternator
 

Hey guys,
Been working on this problem for about a week now. Read all the stuff on the forums of things to try. Started with the easiest and cheapest, the voltage regulator. No dice, still won't charge the batteries. Then changed the crank position sensor. Still no dice. Changed the alternator, still no dice. So now I'm stumped, only other thing I can think of is the brain box is messed up somehow. Any ideas? Or some things I can do to test and assure myself those things are good. I put in all "new" parts, no reman junk. Thanks for any help you guys can provide.

I dunno how far this goes back if its on yer truck or not but my 01 has a battery temp sensor under the drivers side battery, if the battery is hot it wont charge no way:humm:

Thanks for the idea, but mine doesn't have anything like that, and the batteries are cold as can be with the cold front we've got here lately. Keep the good ideas coming friends.

got yourself some wiring schematics? in order for an alternator to produce voltage it has to have voltage supplied to the windings to start with... the regulator adjusts the strength of the charge by the ammount of voltage being put to the windings. usually if its just a regulator problem the external regulator will solve the problem. however junk parts do come in brand new boxes if you get what i mean. simple way to find out if the fields are being excited... hold a wrench to the backside of the alternator; it sucks to it... its fielded. in this isntance i'd look into the output from the alternator to the battery; and even excessive AC volt leakage. in order for a battery to charge direct current has to be applied. that will indicate the rectifier bridge (diode trio) is in tact just in poor condition. also if the rectifier bridge is damaged i dont think it'll stop charging but just charge very poorly

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also pull on your fusible links, if you find one that is "spongy" and stretches i'd be looking for a wiring problem somewhere; get ahold of some wiring schematics and identify what circuit it feeds. fix the short and replace the fusible link... i've also heard the small 3 prong box that plugs into the back side of the dash cluster can cause a no charge situation. they're like 20 bucks a pop too...

Thanks for the ideas, guess I'll be out there with the VOM meter again tomorrow. As for the dash thing, I'll have to pull it apart again, had it apart while installing the gauges on the dash, but didn't notice anything there. I have some basic diagrams for it, but it just shows some of the sensors going to certain pins on the engine control system. Is there any special adjustment to the crank sensor that would cause that condition, such that even though I replaced it, it's still not working properly? Thanks again for the help guys. Seems there are some quirks to how this system works, lots different than a GM 1 wire alternator.

the little 3 prong bugger is on the lower side of the dash around where your PRND21 indicator is

Ok, thanks again.

Bypassing the voltage regulator and shorting the field to ground, the system charges. Now to figure out why it's not telling the alternator to charge with the regulator and PCM system connected in. Is there a fuse or anything I should be checking?

Check for codes??

How on earth do you do that with it? :) Sorry, never had to do it on this truck, I can do it no problem on my Chevy. I'm assuming there is a test port or jumper of some sort? Thanks again for all the help guys, I'm just really frustrated at this point after putting this much money towards it and replacing parts that are likely still good.

just a though if it ends up being the brain box you can wire up a ford external regulator. i didi this in my cummins conversion in my for works good. if it comes to that pm me and ill tell ya how to wire it and the part no for the regulator

It's a relay. Looking under the hood on the driver's side fender, if your truck has A/C you should see a row of 3 relays. The rearmost one is for the A/C compressor, don't remember what the middle one is, but the front one is what the ECM uses to charge. If you have A/C (my truck doesn't) I think you can swap the rear and front relay, fire it up and see if that's it. If it's charging you can get a new relay for about 6 bux from Napa. Autozone also has it. It won't be keyed exactly the same but I cut a slot in the new one and plugged right up.

:U: Yep.The front relay is the ASD relay, just switch it with the A/C relay(the rearmost of the 3). Is the wiring going to the crank sensor O.K? Do you have the correct gap between the crank sensor and the damper? It sould be @ 0.050". But it's probably that relay.

just wondering are you 100% shure on ALL grounds?

don't be so sure that the voltage regulator is good. Mine went bad and let the alternator overcharge (cook) the battery, so I got a new regulator at autozone and still got no charge, took off the alternator and had that tested, put out 15 volts on the stand. put a second new regulator and still nothing. Put the old one back on and got 15 volts. the 3rd new regulator works ok. Takes a few seconds of running before it decides to charge, but works. I think i saw somebody put a single wire GM alternator on, I will seriously consider that route if the alternator itself goes bad.

Thanks for all the ideas guys. I'll have to check on some of that stuff the next time I get a chance to work on it. I'm at my new work location in Jacksonville, FL. My truck is still living in Orlando, FL about 2 hours away. I did check all the grounds, between the alternator and body, body and frame, frame and battery, and from the case of the regulator to the engine as well, all tested zero ohms. My next step is to wire a ground direct from the regulator to the battery. I'm on my 2nd "new" regulator, and it still doesn't charge. As for the relays, I'll check on those too. Also checked the wiring to the crank sensor, everything tested good as well. As for the adjustment, I followed the advise I found online at a different message board that said to fold over a piece of paper 6 times and used that to set the gap. How sensitive is that adjustment? I would assume all those things are working properly if all it requires is me to ground the field and it charges. Seems that everything is working as should, just isn't getting the signal to ground the field and charge as it should. But the alternator works fine. The crank sensor is brand new from the dealer. Thanks again for all the input, gives me some other quirky Dodge things to hunt through and check.

I would put money on the ASD relay. That's what receives voltage from the ECM then sends it to the alternator.

:U::U:

Does your A/C work? How about your Over Drive? Sounds like a bad ECM. Could also be your PCM is not getting a signal from the crank sensor. Check the wiring to the crank sensor, it real wears where it goes beside the belt and where it comes around in front of the head. Also check the sensor gap. Should be 0.050". A little close is better than a little far.

I'm getting voltage to the alternator, just nothing telling the regulator to ground and energize the windings to create a charge. So I don't think it's that relay, or it's been bypassed already if it was. As for the AC, the fan blows, but the clutch assembly has a plug with an end and no matching end on the truck side to connect it to, so no it doesn't work. Someone has chopped into the wiring a bit on this truck, so I know it has some gremlins that someone tried to circumvent. As for the crank sensor wiring, it's got a brand new sensor so the wiring on it is brand new too. I'll try to post some pics of the stuff when I get down there on Sunday to work on it. I'll take a look at moving the sensor closer, but it's a pretty tight gap now. Thanks again for the help guys. Seems like the PCM makes this a lot more complicated system than it needs to be. I miss my GM 1 wire alternator :)

What is your temperature gauge showing, is it getting up to normal temperature, or is it staying barely off cold?:humm:
If the thermostat is stuck open, the engine stays cold, the glow rail controller keeps the glow plugs turned on due to the low engine temperature, especially during winter, with lower air temperature, more use of lights, defrost, etc, the alternater can't keep up with the draw off, due to the glow rail staying on. Altinater is charging, but battery still goes flat occasionally.
Wasted money on battery and altinater replacements,:dang: before I cottoned on to this, I initially found the glow rail stayed live (volt meter) and thought the relay was at fault, but the engine was not getting above 50 deg C. It would charge, after parking (at idle) due to heat soak increasing the engine temperature after a trip.
So this can easily be a non electrical fault, which presents as a very electrical symptom!

Temp gauge reads fine, and it gets up to temp with no troubles. And when I short the field to ground on the alternator, it charges just fine, just can't seem to get it to charge on it's own, time to have the regulator tested somewhere or just replace it again, at least it's only $15. Thanks again for all the help guys, and I'm getting voltage over to the alternator, but I think the PO kinda hotwired the 12V over to there. Does anyone know what voltage the alternator and/or regulator are supposed to see to function properly?

So I tried another voltage regulator and the old girl charges again. Go figure. But it still does kind of a weird thing while charging, the voltage needle swings back and forth when the RPMs are higher than idle, is this normal? I'll try to take the camera with me later today and post a vid of what it's doing. But the good news is that it's charging again.