Electrical problem not running and the generator light is on

  • 1996 DODGE RAM
  • 5.2L
  • V8
  • 2WD
  • 165,000 MILES
I started my truck the other morning and walked off from it and came back a few minutes later and the truck was not running and the generator light was on. It will turn over but will not start. It done the same thing before when I changed the alternator but still would not start. Had a mechanic fix it and he said it was a breaker. Which breaker could it be? Alternator or fuel pump? Thanks.
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have the same problem?
Monday, September 26th, 2016 AT 7:50 AM

1 Reply

Circuit breakers are only used for safety systems that hopefully will come back to life after they trip due to an intermittent problem. Those are head lights and wipers, and they reset automatically.

Cranking fine but not starting has nothing to do with the alternator. Its job is to recharge the battery once the engine is running. The warning light was on because the engine was not running. That is proper operation for the light.

The fuel pump relay is turned on by the Engine Computer at the same time it turns on the automatic shutdown (ASD) relay. That relay powers the ignition coil(s) and injectors, so for a crank / no-start, you need to check for fuel pressure AND spark.

One thing you must be aware of is when you replaced the alternator, you disconnected the battery. Doing that causes the Engine Computer to lose its memory. Most of the learned information will be rebuilt as soon as you start the engine, except for "minimum throttle". Until that is relearned, the engine may not start unless you hold the accelerator pedal down 1/4", you wont get the nice idle flare-up to 1500 rpm's, and it will tend to stall at stop signs. The conditions needed for the relearn to take place are to drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.
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Monday, September 26th, 2016 AT 3:25 PM

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