HVAC only blows hot air - The Unofficial BMW M5 Messageboard (m5board.com)

Dr Pooface · 7th August 2008, 20:39

Even when I have the temp down at the lowest setting. The AC works but it's only chilly, not super cold, and then when I turn it off FOG CITY. I think the ac is cooling hot air as well. Fan works fine. Any ideas...?

jjc1843 · 7th August 2008, 20:50

You are low on freon. R134A. Get a can system from local Auto Store, recharge it yourself. Save $$ from stealer.

The fill valve is locatednext to the valave cover on the right hand side.

DRM · 7th August 2008, 20:51

Quote:

Originally Posted by Dr Pooface

Even when I have the temp down at the lowest setting. The AC works but it's only chilly, not super cold, and then when I turn it off FOG CITY. I think the ac is cooling hot air as well. Fan works fine. Any ideas...?

Advice on intermittent AC issue?

nerio02 · 7th August 2008, 20:54

have you checked your electrical fan (aux fan) in front off the car , iff its doing its thing??

most off the time iff the ac dont blow cold air its because the aux fan dont work...

just start your car, put the ac on and go check in front off the car iff the aux fan runs... you can see it thru the kidney grills.

maybe its that.. any way you dont have to unbold something or get under the car, so its a easy little check up

razahyde · 7th August 2008, 20:59

do you know if your FSU is bad? i THINK thats what causes this, im not sure though. id do a search on the FSu and see if its that.

nerio02 · 7th August 2008, 21:08

Quote:

Originally Posted by razahyde

do you know if your FSU is bad? i THINK thats what causes this, im not sure though. id do a search on the FSu and see if its that.

Fsu normally controlles the speed off the fan inside not the temprature i think; fsu work on data taken from a tempsensor in the dasch..

so iff no irratic speed off the fan i would doubt its the fsu.

offcourse i can be wrong.

aux fan or freon will be it .i can feel it,got cold feet

(j/k)

2002alpine · 7th August 2008, 22:47

low on freon would be my guess had the same problem in my M3

BKH · 7th August 2008, 23:48

A few months ago my a/c quit cooling (suddenly) although the fan worked normally - changing the FSR solved the problem.

Dr Pooface · 8th August 2008, 01:55

OK, you guys don't understand.

My HVAC only blows hot air. When the AC is OFF. At the coolest setting whith the AC OFF it should blow cool ambiant outside air. It blows MAX HOT AIR all the time. Changing the temp setting has no affect, it's always at max hot.

This is not an AC issue. The AC works fine.

DouglasABaker · 8th August 2008, 05:53

Quote:

Originally Posted by Dr Pooface

OK, you guys don't understand.

My HVAC only blows hot air. When the AC is OFF. At the coolest setting whith the AC OFF it should blow cool ambiant outside air. It blows MAX HOT AIR all the time. Changing the temp setting has no affect, it's always at max hot.

This is not an AC issue. The AC works fine.

Does it blow the same temperature air out of every vent (dash, floor, defrost)? Or are they different temperatures?

The immediate fogging leads me to suspect your recirc valve - can you hear a change in the fan when you turn recirc on and off manually?

The only other thought I have on the subject is that it might be your heater control is stuck in the on position, which is to say that your FSU is shot.

d-