1996 Dodge Truck Gen Light

Tiny
NOELY
  • 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

Do you
have the same problem?
Yes
No
Thursday, February 18th, 2010 AT 8:08 PM

28 Replies

Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

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

Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2010 AT 10:08 PM
Tiny
NOELY
  • MEMBER

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

Was this
answer
helpful?
Yes
No
Friday, February 19th, 2010 AT 12:06 AM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

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.

Was this
answer
helpful?
Yes
No
Friday, February 19th, 2010 AT 9:52 AM
Tiny
NOELY
  • MEMBER

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.

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 3:32 PM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

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

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 4:50 PM
Tiny
NOELY
  • MEMBER

See picture with 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?

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 5:15 PM
Tiny
NOELY
  • MEMBER

Picture


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

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 5:19 PM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

I am having a hard time finding that fused in my schematics, can you please tell me what circuit that fuse operates?

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 5:42 PM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

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.

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 7:38 PM
Tiny
NOELY
  • MEMBER

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

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 7:55 PM
Tiny
NOELY
  • MEMBER

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.

Im not clear on where the wiring loom is or what a test light is?

Was this
answer
helpful?
Yes
No
Monday, February 22nd, 2010 AT 7:57 PM
Tiny
NOELY
  • MEMBER

Ok I went to the auto parts store and bought the last four relays. I replaced four out of six and alternated them around but still the battery died on me. I have since found out that these relays all have different strengths so I ordered 4 or so of the PROPER available ones from an online auto parts place. Such as the Ac Clutch relay and the Horn relay etc; When I get them and put them in the right place I 'll let you know how I make out.
Thanks

Was this
answer
helpful?
Yes
No
Tuesday, February 23rd, 2010 AT 10:14 AM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

I notice from your photo that the vehicle has an alarm, that may be giving you some trouble also disconnected for now and perform the following test while you are waiting for parts:
The way to check for a draw is to remove one of your battery cables, it doesn't matter which one take a test light and put one end on the battery cable and the other end of the battery with everything turned off and the doors closed. If the light stays on (the test light), then you have a circuit that is drawing power. While under the hood remove each fuse one by one to see if the test light goes out replace fuse and move onto the next one when you are done with the fuses do the same thing with the circuit breakers, removed them one by one and see if the test light goes out. After you are done with the fuse box under the hood Open up your door, make sure the interior light does not come on if it does take your finger and push the button in on the door and hold it or remove the light bulb, after you have done that, begin to remove your fuses, from the dash one by one and putting them back checking the test light as you remove the fuse and if the test light goes out, that's where your problem is, in that circuit. Let me know what you find. Call me if you need to

Was this
answer
helpful?
Yes
No
Tuesday, February 23rd, 2010 AT 11:12 AM
Tiny
NOELY
  • MEMBER

What is a test light? Can I buy one at the store? After I disconnect a battery cable do I attch the test light to the post I removed the cable from, or the removed cable, or the other one and do I insert the test light into the hole left after I take the fuse out or to the extracted fuse itself? The alarm has been disconnected since I have owned the truck 5 years ago.

Was this
answer
helpful?
Yes
No
Tuesday, February 23rd, 2010 AT 12:38 PM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

You can buy a test light at any automotive parts store, they are not very expensive. Once you have obtained a test light listen to me very closely, remove the positive (+) cable from the battery, you may need an additional person to help you, the test light will have an alligator clip on one end, you can clip that on the battery cable, and the other end touch the top of the battery post, making that connection from the battery cable through the test light to the battery post, if the light comes on you are having a draw, when you've got to this point, with a test light connected to the battery, began to remove the fuses one by one putting them back When you are done testing that specific circuit one by one if the test light goes out you have found the circuit that is drawing the current. Do the same thing with the relay's and follow my previous instructions on checking the inside fuse box of the cab.

Was this
answer
helpful?
Yes
No
Tuesday, February 23rd, 2010 AT 12:47 PM
Tiny
NOELY
  • MEMBER

I did a light test today. I could not do one inside the cab because the light wouldn't reach but none of them are blown. Under the hood however was a different story. In the picture attached you will see I have marked some relays and one fuse with a pink circle. The ones marked in pink do show a light when they are removed and their circuit checked, the other unmarked items show no light when they were removed and their circuits checked.!


http://www.2carpros.com/forum/automotive_pictures/485513_fuse_Box_2_1.jpg

Was this
answer
helpful?
Yes
No
Sunday, February 28th, 2010 AT 6:06 PM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

I don't think your understanding how to do the test, because you said "I could not do one inside the cab because the light wouldn't reach" the test light doesn't have to go anywhere except on the battery, remove the positive (+) cable from the battery, you may need an additional person to help you, the test light will have an alligator clip on one end, you can clip that end on the battery cable, and the other end touch the top of the battery post, making that connection from the battery cable through the test light to the battery post, if the light comes on you are having a draw, do only what I told you just now and let me know if the light comes on.

Was this
answer
helpful?
Yes
No
Monday, March 1st, 2010 AT 10:13 AM
Tiny
NOELY
  • MEMBER

Ok I did what you said and the light went on. if what I did in the picture is right.


http://www.2carpros.com/forum/automotive_pictures/485513_005_1.jpg

Was this
answer
helpful?
Yes
No
Monday, March 1st, 2010 AT 2:53 PM
Tiny
DR LOOT
  • EXPERT
  • 2,320 POSTS

That is correct. Now with that test light in that position, remove your fuses one by one and replacing them, when the test light goes out you have found the circuit that is draining your battery. Let me know what you find out

Was this
answer
helpful?
Yes
No
Please consider a donation if we helped you
Monday, March 1st, 2010 AT 8:01 PM
Tiny
NOELY
  • MEMBER

Success! The photo shows the fuse that was causing the problem with a blue spot on it. My radio still doesnt work and I have checked the fuses, all of which look fine, unless I shorted my radio out? I took the truck for a ride after using another car to charge it and it started no problem.

Was this
answer
helpful?
Yes
No
Tuesday, March 2nd, 2010 AT 12:27 PM

Please login or register to post a reply.

Related Battery Light Questions

Recommended articles