In 4wd - electrical power fade 84' Yoda

Here in the Northwest we get snow. I had the 4wd engaged, as I was
heading up a long driveway the trucks
head lights started to dim and the engine felt like it was lossing
power. Now this has never happened before.
The truck's alternator is charging, I also noticed that the alt
charging meter in the truck did spike down and
does go down once in awhile,this only seems to happen once the 4wd is
engaged. when it's in 2wd it's fine. Any comments would be
helpful.

"pacaguy" <pacaguy.DeleteThis@config.com> wrote in message
news:705544d9-a1b7-4111-85f2-b59aa6203f2b@i12g2000prf.googlegroups.com...
> Here in the Northwest we get snow. I had the 4wd engaged, as I was
> heading up a long driveway the trucks
> head lights started to dim and the engine felt like it was lossing
> power.

Your alternator was not charging at that point.

Now this has never happened before.
> The truck's alternator is charging, I also noticed that the alt
> charging meter in the truck did spike down and
> does go down once in awhile,

That also indicates your alternator is not charging.


this only seems to happen once the 4wd is
> engaged.

Only thing that comes to mind is possibly a broken motor mount that lets the
engine shift under load. You may have been using more throttle in 4WD and if
the engine moves it may be flexing a wire harness. I can't think of any other
reason that 4WD would make a difference.


when it's in 2wd it's fine. Any comments would be
> helpful.

If it doesn't do it in 2WD check to see what is different when you are in
4WD. You might just want to do a complete check of your charging system,
including testing your alternator under load. Also make sure all your battery
and charging system electrical connections are clean and tight.