Engine/Transmission (1994 - 1998) Charging System ain't workin'

[KcoleKennyc]

Need help bad. Been down about three weeks. Have a 97 Dually. First noticed something going wrong when headlights started to flicker and not burn as bright as usual. It did this off and on for a week or so. Then all of a sudden I lost the speedometer, tach, air conditioner compressor, et. . Volt meter shows no charge. Went to Autozone, purchased new alternator, no fix. Had new alternator checked, no problem. New batteries, no fix. Ran diagnostics, says bad PCM. New PCM, no fix. Cannot find any loose connections. Up for any ideas.



Kenny

 

[Gary - K7GLD]

Dunno about your particular year model - but when I had the same problem on my '91, it was a $12 voltage regulator...

 

[KcoleKennyc]

From what I've been told, the voltage regulator is built into the PCM. ??

 

[illflem]

Bad battery temp sensor under the pass side battery???

 

[Bob4x4]

Check your engine speed sensor,The PCM needs to see the engine spinning to turn on all those functions you say have qiut working

 

[KcoleKennyc]

illflem,

forgot to mention I checked the Bat temp sensor, no fix.



Thanks.

 

[KcoleKennyc]

Bob4x4

Please tell me a little more about the engine speed sensor, like where is it and how would I check it??



Thanks. . Kenny

 

[HoleshotHolset]

RPM sensor is bolted to the block (via the gear case cover and gear case... . ) and sits very close to the harmonic balancer/crank pulley combo.....



Hope this helps,

Matt

 

[cmonroe]

CHECK YOUR 140 AMP MAIN FUSE IN THE FUSE AND RELAY BOX BEHIND THE BATTERY ON THE DRIVERS SIDE.

 

[KcoleKennyc]

Thanks cmonroe,



I'll try that...

 

[KcoleKennyc]

Just an update. .



No, I haven't got the truck charging yet. Its now at the second dealership. The second dealer has traced and checked all wiring under the hood, pulled the dash and checked all wiring. The first dealer ran a scan and code said bad PCM. Got a PCM from a scrap dealer (boy these things are expensive) and it didn't fix the problem. Second dealership says it has got to be the PCM. Ordered new PCM. Same thing. Today (Monday 06-03) they are scratching their heads and so is Chrysler. Its been there for the last two weeks and the dealer has been on the phone with Chrysler every day. I haven't had a truck for over a month. A little disgusted.



Just Venting

 

[SRehberg]

You said you checked all the connections; did this include the grounds for the PCM etc. ? They are just as important as the hot side, and in your climate they could be corroded to the point of insulated. If you have the Chrysler service manual, check out the diagram on 8W-30-43. The main ground connection is shown on diagram 8W-15-12, G119. It is located on the right side of the engine block. How about the connectors that hook onto the PCM, a bear to check, but if nothing else shows. Just my 2cents.

 

[KcoleKennyc]

SRehberg,



As soon as the dealer wakes up, I'll pass along this information. I think it will be a simple fix such as this wherever it is.

Thanks, I'll keep you posted.

 

[Strick-9]

Same thing happened to me once.



It was a bad ground on the PCM. I believe there are more than one. I found the problem at the engine speed sensor plug. No ground, therefore no signal to turn the rest of the accessories on. (speed, tach, alternator, AC)



The ground wire was still attached to both the PCM and the ground, but when I spliced in another wire and grounded it, all was well.



Let us know,

Chris

 

[shendren]

i am also looking for possible electrical problems. my tc is going in and out bad. i can only go 45mph. i have tried quite a few things. where do i find the ground for the pcm? i pulled off the black plastic cover to find an aluminum? box with some torx and hex heads. do i pull these? is the ground inside? thanks. scott.

 

[SRehberg]

Scott, the only ground up at the PCM is the two wires coming from the ground connection. The manual says the main ground is on the right hand side of the engine block. Check some of the other posts here, as one of the other members (Strick-9)said he found his problem at the speed sensor; The main PCM ground would be the first to check. I think there are other threads regarding TC locking and unlocking, related to the TPS on the pump. Hope this helps

 

[KcoleKennyc]

Wow!! Has this ever been a trip. The truck is back up and running after almost seven weeks and two dealers. Oo. . Talked to the dealer Monday and told him what Chris (aka Strick-9) had posted. The dealer was a little perturbed at the suggestion because he and Chrysler had been running wires for two weeks with no luck. I guess this seem to simple to be a fix. Said he'd already checked the speed sensor and it was fine. After he calmed down a bit he did promise to check the speed sensor ground. Wa-La!! THIS WAS IT. !!! Everthing came up fine.

I can't thank you guys enough for the help. A special thanks goes out to Chris for hitting the nail on the head. Also, to Bob4X4 for the hit on the speed sensor. I'm not sure how much longer and how many more dealers (and dollars) it would have taken to find the problem. Isn't this a great forum. I'll be here for a long time!!



Thanks again guys



Also, a thanks would be in order for Jim Anderson of Anderson Chrysler & Jeep in Jackson, Alabama for their time and effort spent locating the problem. Thanks guys...



Kenny

 

[shendren]

ok, maybe i'm a little dense... . where exactly are the two grounds at the pcm? i've unplugged the 3 connectors and pulled the pcm. do you have to open the box up and look inside? thanks. scott.

 

[Missouri Mule]

No the ground for PCM is remote location (away from PCM).



The main ground is on drivers side, front side of engine about six inches in front of heater grids.



The pcm is grounded here plus this allows the pcm to give grounds to sensors that feed it data.



This ground location I believe handles three to four ground wires.



If you have Dodge service manual you look in connector pin -outs section to see what connector pin does. That way you know which is supposed to be ground wire.



The Asd relay supplies power and line voltage ( or that is the way I"m reading it) to PCM. The engine speed sensor turns on the ASD relay.

 

[SRehberg]

Missouri Mule... now you have my interest. I was looking in the '96 Dodge service manual, and it showed the ground connection for the PCM at G118, located on the right side of the block. Is my book in error (can't hardly believe they would make a mistake LOL) but if I ever need the location, I'm going to correct the manual. It's no good if the info is inaccurate.



I'm glad to hear the truck is back up running and the problem was easy to fix, albeit expensive and time consuming.