1990 740 Turbo electric fan question

n1cjs · Post by **n1cjs** » 23 Aug 2011, 15:26

I'm trying to figure this beast out... this is my second question for the forum...

Why would my electric fan come on if the A/C is not activated?? My A/C has been broke for quite some time, to the point where there is no juice left in it. So why would the electric fan come on, if the motor has a clutch fan already?? And when said fan does come on, it REALLY draws the motor down and you can see a big change in the voltage meter too. Not down in the red area, but down from normal.

Any thoughts??

Thanks a bunch in advance, Chris

Post by **jimmy57** » 23 Aug 2011, 15:54

The fan has a thermal switch stuck in radiator. If it gets warm enough the electric fan kicks on. There is another switch on high side line that triggers fan for a/c high pressure.

n1cjs · Post by **n1cjs** » 23 Aug 2011, 16:46

Well... that answers that. So there is two modes of cooling.

Now is it normal for the electric fan to drag down the motor so hard. It takes about 200 rpms right off the idle. Could there be an issue with the alternator??