Rear defrost strange problem

[wade623]

I just noticed that when I turn on the rear defrost the car idles in nutral at 1000 rpm as soon as I turn it on then when I turn out off it goes back to normal I have no idea w
hy its doing this so I need any ideas on what is going on

[MagicRat]

I am not certain about the your engine, but it might have a throttle 'kicker', which boosts the idle speed to increase alternator output, most likely via the IAC.

At idle, alternators are producing only a fraction of their rated electrical output. The defroster grid demands a lot of electricity. If the alternator cannot supply this, then the battery becomes drained. So, a slight increase in idle speed will increase alternator output.

But this is my best guess. Perhaps an Aurora owner might add something.

[wade623]

heres a video it sucks i took it on my phone but you can see that it goes up when i turn on the defrost



http://www.youtube.com/watch?feature...&v=KTyXiNzb4UI

[peeweewasblue]

I had my defroster on yesterday and it does the same thing, so I guess it is normal.

[wade623]

ok then it just didnt seem normal but thanks anyway