Mechanics

GEN LIGHT

1996 Dodge Truck

Electrical problem
1996 Dodge Truck V8 Four Wheel Drive Automatic 170000 miles

I recently had my Transmission rebuilt. After I got the truck back the battery kept dying on me and I needed a lot of jump starts until last week when I bought and installed a new battery. This didn't work so I went on advice here and bought and installed a new Alternator. This did not change the situation either. When I start the truck the GEN light comes on in a matter of minutes. I have checked all my fuses and they look fine. The ones in the small black or covered boxes I could not check. Also my horn and radio seem to have blown or are not getting enough power. What are my options to finding out whats wrong and is it fixable by me. I dont want to risk driving to the garage and end up breaking down on the street because the battery died.
Please help
Avatar
Noely
February 18, 2010.



Chrysler Corp. Light trucks use a Denso generator. The generator consists of a rotor, stator, rectifiers, front and rear covers and drive pulley. Voltage regulation is controlled by the Powertrain Control Module (PCM) on all models except diesel. I am assuming your truck is not a diesel. The PCM monitors critical input to control fuel injection, ignition, emission and other engine management functions. The PCM is also programmed to monitor charging system related circuits: Battery feed to PCM. Generator field control. Battery charging voltage (high & low). If a problem is sensed in a monitored circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM memory and Malfunction Indicator Light (MIL) will come on, provided specific criteria have been met. DTCs can be read using MIL, Chrysler's Diagnostic Readout Box (DRB-III), or a generic scan tool. If you don't have a scan tool, go to your local parts store and have them download codes if there is any.
INITIAL CHECKS Before proceeding with charging system diagnosis, ensure following conditions are met: Battery is fully charged and in good condition. Battery cables are in good condition with connections clean and secure. Generator belt is in good condition and properly tightened. Generator and PCM wiring harness connections are clean and tight. Engine ground strap is in place.
UNSTEADY OR LOW CHARGING Check for loose generator belt, charging resistance too high, loose generator ground wire, corroded battery terminals or faulty generator.
SELF-DIAGNOSTIC SYSTEM If a problem is sensed in a monitored circuit, a Diagnostic Trouble Code (DTC) will be stored in PCM and MIL will come on, provided specific criteria are met. PCM will then enter limp-in mode, substituting information from other sources to compensate for component failure. Vehicle is operational in limp-in mode, but driveability may not be optimal. A specific DTC results from a particular system failure. DTC only indicates problem circuit. It does not identify specific component failure in the circuit. If problem is repaired or ceases to exist, PCM automatically clears DTC after 50 ignition on-off cycles. DTCs can also be cleared using scan tool.
I will most likely need the codes before I can assist you, I want to check the wiring looms in the engine compartment and around the transmission make sure the wires are in good condition. And that the transmission guys did not damage the loom or pinch any wires between the engine and the transmission

Dr Loot
Feb 18, 2010.
Thanks for your reply. I have purchased a scan tool and expect it to arrive in the next few days. When it does I will get any readings it gives and post them in a reply for you to look at, here's hoping it doesnt cost me a lot.
Thanks

Tiny
Noely
Feb 19, 2010.
OK, while you are waiting for your scanner checked the list I sent you, and try to do some of the diagnostic procedures, as so as you download the code I will be able to assist you better.

Dr Loot
Feb 19, 2010.
I received the scan tool. When I tried it out it read NO CODES. The battery is dead all the time now and I have to jump it with the wifes car to even start it. There are 3 fuses under the hood, the same type as are under the dash and one of them blows each time I replace it. I will try the scan tool again tomorrow when its light out. Im stumped.

Tiny
Noely
Feb 22, 2010.
Is this the fuse box under the hood you were talking about?


http://www.2carpros.com/forum/automotive_pictures/307270_Graphic_dodge_1.jpg



if that is correct tell me which fuse in its


http://www.2carpros.com/forum/automotive_pictures/307270_Graphic_1996_1.jpg


Dr Loot
Feb 22, 2010.
See picture wioth arrow. The fuse keeps blowing out. It is a 20 amp fuse. If one of those 'black' box fuses are blown could that be causing my problem?

Tiny
Noely
Feb 22, 2010.
Picture


http://www.2carpros.com/forum/automotive_pictures/485513_fuse_Box_2.jpg


Tiny
Noely
Feb 22, 2010.
I am having a hard time finding that fused in my schematics, can you please tell me what circuit that fuse operates? I will give you my cell number you can call me if you wish (785) 218-7350 Dave.

Dr Loot
Feb 22, 2010.
Sorry I found it, disconnect all of your plugs on the wiring loom to the A/C Compressor Clutch, Horn Relay, Horn Note & A/C Compressor Clutch, one of those systems is shorting out, unplug those, then remove your battery cable, it does not matter which one, put a test light in between the of cable and the battery, if the light comes on you still have a short, if the light does not come on plug-in each component until the light comes on and that is your problem lies.

Dr Loot
Feb 22, 2010.
The fuse says 20 amp Horn on it. Also remember the radio is out but the fuse looks fine. I will try what you said tomorrow and let you know how I make out. Thanks for your great help. Talk later

Tiny
Noely
Feb 22, 2010.
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