Engine/Transmission (1994 - 1998) what do you know about alternators

[Piersol]

today driving to work the "gen" light came on in my truck (1996 with auto trans. 109000) I can't say it was on ever since I started it but can't say it wasn't either. I turned on the headlights and heater fan full blast and the gauge stayed at 15 volts and never moved. I pulled off the side of the road and restarted the truck and the light went out. Is this a sign of trouble ahead or just an electrical glitch. I always thought an alternator either works or it doesn't. New belt 30,000 mile ago. Any thoughts.

 

[BillGotthelf]

If you have an electric meter set it on the lowest dc voltage setting over 12 volts. Test at battery connections both at idle and above 2000 rpm. Voltage should be at 13. 8 or higher and as long as engine has warmed up should not increase more than . 1 volt with rpm increase. I have had wierd electrical one time glitches happen on my 96 also. Lost fuel gauge-turned off engine and restarted everything okay. :--)

 

[C Schomer]

Maybe your batteries are going. Sometimes they can drive everything nuts! Clean all the terminals. I don't know how this newer stuff works but the batt light used be signaled by the regulator - now it probably comes from a computer. 15 is a bit high but if it holds with everything on, sounds like the alt. is OK and the rotor is getting a steady (but slightly high) excitation voltage. Bad batteries CAN cause charge irregularity too! Craig

 

[ronco]

Didn't I read here that the PDC determines charge rate, and therefore, charge voltage? Does that apply to all Dodges, or just some of the later trucks? I agree with Craig that bad connections can to bad things to wiring! Check all grounding wires/straps while you are under there.



Ronco

 

[Piersol]

I hope it is not the batteries. They are 2 years old and they are the optima red tops. I spent alot of money on them and if it is them I will buy the cheapest batteries I can next time if I only get 2 years out of them. I don't know if this is related or not but 3 or 4 weeks ago Both the brake light and ABS light came on. I had good brakes. Did the same thing, shut off the engine and restarted and lights went out never to come back on.

 

[Bob4x4]

I Had a 97 in the shop about a month ago. . intermittent volt meter drop with electrical load. Found cleaning the battery connections was all it took to remedy . The batteries were only installed by the owner 2 weeks earlier.



Bob

 

[Piersol]

I'll check the connections, however, it has been between 4 and 10 degrees when I turn it on in the morning and it fires right up almost instantly. I am waiting on my block heater plug wire to be delivered so I haven't even been using the block heater.

 

[Pit Bull]

If you have a Batterys Plus store in your area they will check the alternator and batteries for free and if the terminals are dirty they will clean them for free.

 

[radixr]

Uh, Oh!

Jim,



When you replaced your batteries, did you have to screw down the clamping bolts quite a bit (because the red tops are not as tall as the OEM batteries)? If so, you may have penetrated a wiring harness below the battery tray with the end of the clamping bolt and that could be causing your electrical problems.



This happened to me and I almost went nuts trying to locate the cause. The driver's side battery is the one to look at. :{ :{

 

[stick]

Piersol:

My 97 has been doing the same thing for about a month now. I don't think it is a battery problem, because all my voltages are allright, and everything is clean.

Something is triggering the GEN light to come on and it seems to only take a second to happen, because I have been keeping an eye on it. I have tried to retrive any trouble codes with the key method, but nothing comes up.

What I am afraid of is it might be the voltage regulator, and it is located in the PCM !

If you figure anything out please let me know.



Thanks Stick

 

[Piersol]

radixr, Are you talking about drivers side towards the fender or towards the engine. The screw is free of any wires on the engine side but as far back as I can feel it appears that it is free on the fender side too. However there does not appear to be good way to tell for sure.



Stick, I hear you about the voltage regulator. It always seemed to me that 15 is too high, however it is a best guess. If you can understand my explaination here is where my needle reads. There is a line at 14 volts. If you can imagine the width of the needle. that is about how much space I have before where the actual needle reads. As I recall that is where it has been since new. I always thought 13. 4 volts is where you should be charging at. My pcm was replaced under warranty at about 32,000 miles but that still means that it has 77,000 miles on it and 4 years old.

 

[radixr]

It's the fender side. I had to remove the battery tray to find it.



Stick, I see you have red tops too. I would check for a pierced wire bundle under your battery tray also.

 

[stick]

radixr :

Sure i'll try anything ! Allthough my batteries have been in their almost three years. You never know.



Stick

 

[Greg W]

Alternator problems

I had a similar problem when my 95 truck hit about 250 k miles. The battery was charged well and all connections were good, the voltages at the alternator looked good and truck started very well.



I changed the brushes in the alternator, it was a little round plastic peice that housed both brushes. It was about $5 and was very easy to change.



I have not had the problem since changing it. Something to look at and very cheap to fix. I hope this helps.



Greg

 

[SEmerson]

In my 97 I had this happen. I looked all over to find brushes to rebuild it. I never could find any. I finally replaced the alternator. Worked fine ever since.