Electrical problem in 9000

I recently had my 97 9000 Aero in for repair at my excellent local repair
shop. I had them replace the ignition switch in the steering column. While
there, I asked them to check the electrical system generally because of
something I'd noticed. As I'd drive down the road, I noticed that the
voltage on the dashboard indicator would go up and down. Anywhere from 11
volts to 14.2, usually up around 14 where it belongs. They found that the
alternator was putting out considerably less than the correct amount so I
had them replace it. I still have some fluctuation in the reading on the
gauge but much less than I used to have. But, as I drive along, I do notice
a dimming of the headlights from time to time. No new load (like an a/c
compressor) kicking in, just driving down the road. The lights come back up
to normal brightness in a few seconds. The shop is aware that the voltage
still isn't right but none of us are sure where to check next. The battery
is about two years old, on a 60 month Interstate battery.

Anyone have an idea on what might be causing this fluctuation in the
voltage?

Thanks.

Two items I would check would be the light switch itself and the headlight
relays - also the wiring going to each of them around the points where it
meets the connectors and the relay panel. I am not certain, but I believe
that the usual failure mode for the headlight relay is simply no light at
all from one or both of the lamps, usually the high beam - but still it is
not a bad place to start. What usually happens is that the relay itself is
not bad but the solder joints begin to fail in the relay board where the
contact pins that connnect the relay to the relay panel (this is in the box
in front of the battery, not the panel above the fuse board under the airbag
in the passenger footwell). Typically the relay problem can be solved by
simply re-flowing the solder joints with a low watt soldering iron and maybe
a bit more electrical solder - but as I said, that failure usually isn't one
of dimming and brightening.


"Milo" <milo_dhuey RemoveThis @yahoo.com> wrote in message
news:xDZej.2883$jX4.1187@trnddc07...
>I recently had my 97 9000 Aero in for repair at my excellent local repair
> shop. I had them replace the ignition switch in the steering column. While
> there, I asked them to check the electrical system generally because of
> something I'd noticed. As I'd drive down the road, I noticed that the
> voltage on the dashboard indicator would go up and down. Anywhere from 11
> volts to 14.2, usually up around 14 where it belongs. They found that the
> alternator was putting out considerably less than the correct amount so I
> had them replace it. I still have some fluctuation in the reading on the
> gauge but much less than I used to have. But, as I drive along, I do
> notice
> a dimming of the headlights from time to time. No new load (like an a/c
> compressor) kicking in, just driving down the road. The lights come back
> up
> to normal brightness in a few seconds. The shop is aware that the voltage
> still isn't right but none of us are sure where to check next. The battery
> is about two years old, on a 60 month Interstate battery.
>
> Anyone have an idea on what might be causing this fluctuation in the
> voltage?
>
> Thanks.
>
>
>
>