NEON REGULATOR

[Steve P.]

99' Neon. Battery light on dash lights up. Daughter calls me. I put the tester on the battery. It reads good. Start the car and the charging system is just barley charging. NOT GOOD.. Have my buddy pull the alternator and take it to the rebuild shop. He bench tests it and says, (this thing is perfect). 130 amps. I find out the regulator is built into the COMPUTER....  (WOW, YOU HAVE TO BE SH!TTTTTING ME)!! Well, it is.. $300.00 computer and it has to be programed by the dealer at more cost. My next thought was to hit the bone yard and buy one for $40.00. It should not need to be programed as it will come out of another 99 Neon with like engine. This brings me to my question: Does anyone know another way or a better way to fix this problem? My daughter is saving to buy a house and this is a high mileage car. The balancing act is hell right now.

I for one cannot believe they put a $10.00 replaceable part INSIDE a $300.00+ sealed computer!!!!! 

[Plumcrazy]

Voltage regulators have been inside the PCM's since the 80's with failures being extremely rare.

With the engine running check to make sure you have B+ at the dark green/orange field wire.
If you do I would then check the control circuit between the alternator and PCM.  Its a dark green wire that goes to cavity #4 in the #1 PCM connector.

[Steve P.]

Voltage regulators have been inside the PCM's since the 80's with failures being extremely rare.

With the engine running check to make sure you have B+ at the dark green/orange field wire.
If you do I would then check the control circuit between the alternator and PCM.  Its a dark green wire that goes to cavity #4 in the #1 PCM connector.

Hey Plum, Thanks for getting back so quick.  I take it (B+)= (Battery Positive). And if I have Battery Positive at the DARK GREEN/ORANGE field wire I should have the same at the #4 pin in the #1 PCM connector. If I do have Battery Positive at the #4 pin it would lead you to believe it is the regulator that is the problem and the PCM will need to be replaced??  I just want to make sure I explain this right to my buddy doing the work for me. I can't do the leaning with my back... I sure appreciate it man...

[Plumcrazy]

Yes, B+ is battery positive voltage.   The alternator field is supplied B+ by the autoshutdown relay. Thats why the engine has to be running.

If you have B+ to the alternator field you then need to check the circuit between the alternator and PCM.  To be safe I would do it this way.
Unplug both the alternator field connector and PCM connector.  Ground the dark green wire at the alternator connector.  Connect a test light with a plain light bulb not a neon bulb to the battery positive cable. When you probe it into cavity #4 of the PCM connector it should light.  If everything works the way it should then the only thing left is the PCM.

Here's a photo you'll need of the PCM connectors

[Steve P.]

Thanks again for your help Plumb. Sorry it's taken me so long to get back to you on this. Things around here have been totally nuts lately.

We jacked the car up high enough to actually SEE what is what under there and when my buddy Ray said, (OH SHIp), I knew it wasn't good.  Long story short, the oil pressure switch was leaking and sending oil directly into the wire harness containing the alternator wires and the 02 sensor. The oil had broken down the insulation on the wires, (all of them), and caused hell. We cut back the harness tape and separated the wiring. Cleaned all with carb cleaner. Air dried and put 2 coats of liquid tape on all the wiring. Changed the sender and tried it. Everything works,,, BUT,,, it is still charging @ 13.6 volts with or without the A/C and headlights on. I like to see 14.2-14.3.  I don't know if maybe this hasn't been charging this way since my daughter has owned it. The charging light is not on and she says it is running better than it ever has. It has leaked oil ever since she has owned it, more than a year. It was supposed to be a short term car. I hope that Liquid Tape can deal with heat. All that wiring is only about 6 inches away from the exhaust pipe. 

[Plumcrazy]

If you had Chrysler's scan tool you could check to see what the target charging voltage is but I wouldn't be to concerned with 13.6 v

Aren't you glad you didn't buy a computer. 

[Steve P.]

You're damn right... Thanks again.  I did make a run to the bone yard last Sunday. Many Neons in there, but most didn't have computers in them.  We are going to keep an eye on it for a while. I'm telling ya, the way things have been going for me lately, I should change my name to firefighter. All I have been doing is putting out fires. First was the double fiasco with my younger daughters Oldsmobile A/C. Then the Neon. Then legal shiP. (Well, that's been ongoing for what seams a lifetime)! Then after having a great day on Sunday, I get a call at my buddy Rays shop that my younger daughter just got in a wreck.  Man, I need to win the Lotto.....

Did I mention she was doing this?    It's bad enough we gave her my wife's car, but now I have to build her a drag car too!!

[TylerCharger69]

I had an old  Plymouth Reliant pos car   and   the regulator in the computer went out......it cost more than what the car was worth  so  I sold it to a junkyard.

[Steve P.]

More on the NEON..

Friday I had to change the oil pressure sending unit, (AGAIN), as it was leaking oil AND turned on the oil light. It did give me a chance to check out the liquid tape I used to repair the wiring. I think I like that stuff!! It stayed flexible and is not sticky. Works well and it's even a bit closer than I would like to the exhaust pipe. No choice there...   

Much more screwing around with that lowrider and I'm going to have to buy a lift..


That's what I keep telling my wife anyway... 

[TylerCharger69]

NEON.....isn't that a disposable car?...kinda like  Daewoo?...lol

[Steve P.]

NEON.....isn't that a disposable car?...kinda like  Daewoo?...lol

Be carefulll now!!!!!   NEON'S say (HI)...  Daewoo's say (BOOM).........   

[TylerCharger69]

lol...maybe that was Escort im thinking of...lol