The charging system operation of our vehicles is a little more subtle
than most realize. The dash instrument cluster is REQUIRED for
alternator charging to take place. The instrument cluster has a circuit
built into it that provides the initial field activation current for the
alternator so charging mode starts up. If the wiring connection between
the circuit foil in the dash and the alternator is faulty, the
alternator will never start charging.

In other words the alt led on the dash is not just an indication that
the alternator is/isn't charging, it is part of what makes the
alternator work.

Mark

neil wrote:

> ...........
> I wondered if aux battery might have been run too low for charging
> systeme to deal with.
>
> I will check/do those things and also measure if 12V coming from blue
> wire with engine running. Something I was wondering about.
>
> Thanks again,
>
> Neil.
>
>
> On 4/12/07, Mark Drillock <mdrillock@cox.net> wrote:
>
>> Neil, don't panic it is probably something simple.
>>
>> First, charge the batteries if they need it.
>>
>> Then unhook the blue wire from any camper related stuff you connected it
>> to. Now, does the alt led come on when the key is on but engine not
>> running? If not, how about the ox and oil pressure lights?
>>
>> Mark
>>
>>.............