problem with ac/fan
 

Last three road trips i've made the AC fan shuts way down after about 2 1/2 hours of driving (ambient temp outside has remained the same- hot). Even when I punch MAX it doesn't change much- you can hear lots of fan noise, but not much air coming out any of the AC vents- body, dash, floor. (MAX setting when I first start the car is fine, cools down quickly, lots of air blowing through the vents). For the first couple of hours everything is fine- no changes made to any of the settings i-drive or otherwise. Just a diminution of air coming out. Car is a 2008 4.8, about 16,000 miles. Anybody experience anything similar? Thanks. :dunno:

typical bmw... end stage resistor

Theres a SIB about blowing hot air after a drive rather than shutting done .. may be related .. it's to do with warm air flowing past a sensor or something.. will try and find it...

Do you have rear A/C?

I know with mine, if the fan in the rear is turned up, the air flow to the front is greatly reduced.

yes, but it wasn't blowing out of there either.

update on ac/fan problem
 

Took to dealer for repair- said it was the final stage resistor. Brought "repaired" car around for me to drive home, I get in, and a loud low rumblng noise is coming from the fan (not there before). Tech said the short in the resistor must have caused the fan blower get out of balance. Now they want to replace the blower. Not in stock, will be in early next week. Will try again.

Sounds to me like an assembly screw-up and the squirrelcage is rubbing. Maybe they dropped the blower assembly. In any case, a new fan and reassembly should fix it.

lol did i not call it? end stage resister... very common amongst bmw

You are right- but you should have warned me about them screwing up the blower! (just kidding)

actually the blower is common too... so you do have a point ;) in the last 10 years of owning bmw's i've had 4 end stage resister go bad and 2 blower replacement AND a heat exchanger replacement. its just something that bmw can't ever get right, their HVAC system.

in the summer of 2002, the end stage resister was on back order for like 4 week, it was totally f'd up. I ended up writing BMW NA calling my ultimate driving machine an ultimate paper weight because it was useless in the 90-100 degree summer we had. after the letter the part miraculously showed up.

-john