I noticed a couple of days ago that my volt meter goes down considerably when I turn the de frost button for the back windo. I'm wondering if it'* normal cause it doesn't go down any other time besides that.

The rear defrost takes a lot of power - I wouldn't be surprised. How far does it go down?

almost to the red zone,

It is a big draw - However your electrical system may not be completely healthy. It would be good to know what the actual voltage is when it goes near the red zone.

Mista, I did some homework for you. Mine draws 0.2 to 0.3 volts (aren't you glad I installed a voltmeter? )

But keep in mind I have a very strong battery and a DP 160amp alt. Your alt is probably only 105 amps, and it sounds tired to me.

Consider changing the battery and Alternator soon.

Mine does the same thing, when I am stopped, especially at night. This was discussed either in another thread, or while we were survivng over at MNBC, and it seems to be the norm for our cars. With all the computerized gizmos and what not, the stock alternator is just barely enough to run the car. Probably a "cost management" thing at the plant.

But, I'll be upgrading the alternator to 160 or 200 amps come spring.

Mine only draws that less than half a volt at night with everything on, or during the day with nothing else on.

I think the stock 105 alternators are a little underpowered, especially for an SSE or SSEi.