[heyjude076]

I have a 1996 Astro Van. When the engine reaches operating temp the voltage will slowly drop till the light comes on when ever I put a load on (fan, lights, etc). If I shut off the load the voltage will rise back to 14V. Only happens when the engine is warm. The alternator is less than a year old and checks out OK. Did not notice this till a few weeks ago. Battery was 5 yrs old so I replaced it. I am thinking this is a loose/corroded connection. I have checked the obvious places and now looking for suggestions.

Thanks

[burnt olds]

Originally Posted by heyjude076

I have a 1996 Astro Van. When the engine reaches operating temp the voltage will slowly drop till the light comes on when ever I put a load on (fan, lights, etc). If I shut off the load the voltage will rise back to 14V. Only happens when the engine is warm. The alternator is less than a year old and checks out OK. Did not notice this till a few weeks ago. Battery was 5 yrs old so I replaced it. I am thinking this is a loose/corroded connection. I have checked the obvious places and now looking for suggestions.

Thanks

you still got the rubber coating on the battery cables ?
they corrode between the innards ,cut off and clean

[LATECH]

Originally Posted by heyjude076

I have a 1996 Astro Van. When the engine reaches operating temp the voltage will slowly drop till the light comes on when ever I put a load on (fan, lights, etc). If I shut off the load the voltage will rise back to 14V. Only happens when the engine is warm. The alternator is less than a year old and checks out OK. Did not notice this till a few weeks ago. Battery was 5 yrs old so I replaced it. I am thinking this is a loose/corroded connection. I have checked the obvious places and now looking for suggestions.

Thanks

The battery is a good suspect as it should have ample reserve capacity and hold a charge well for a good length of time. You should be able to hit it with a load test ( after charing the battery with a charger) and get 200 amps without falling below 10 or 9.6 volts and sustain that for about 15 seconds. If you have a midtronics tester they are pretty accurate and take all the guess work out of it. If the battery tests good then I would suspect the alternator has an internal problem like diodes open circuit or a regulator that is washing out with heat.

[heyjude076]

Originally Posted by latech

If the battery tests good then I would suspect the alternator has an internal problem like diodes open circuit or a regulator that is washing out with heat.

Since it was doing this before the battery was replaced I am doubting it is the battery. I did notice yesterday that it does this with out a load only not as radical. The voltage slowly drops to <12V and then climbs back to 14V. It is almost like a hot/cold cycle. This is pointing me to the alternator even though it is almost new. Will swap it out this weekend.

Thanks for the suggestions.

[T-bucket23]

You most likely have a bad connection. I would check all grounds and main feeds. I would be willing to bet you find a bad ground connection somewhere. As the engine warms the connection will get worse if it is loose.