BimmerFest BMW Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
My 2001 750iL will only blow cool air out the dash vents. While on Auto, hot air is blowing out the defrost vents (defroster is not on) and sometimes out the footwell vents.

Today's ambient temperature is 50 degrees Fahrenheit, and I had the temperature set to 72 degrees F, and the stratified air thumbwheel set to cool (I have read that if you set it all the way to cold, it will cause the system to pull in the cold air and try to compensate by putting out hot air on the lower vents). The air conditioner was not on (should not have needed it with the ambient temp being so low). However, the air temperature in the car was uncomfortably warm. If I switch the HVAC from Auto to the middle buttons (dash vents), the air ceases coming out of the dash and footwell vents (as it should).

I am reading this: file:///C:/Users/Administrator/Downloads/08%20IHKA%20E38.pdf and it seems to indicate that you can never have cool air blowing out the defrost and floor vents. Is that correct?

I have replaced the auxiliary water pump/heater valve previously.

So, owners, is it possible to ever have cool air in the footwell or from the defroster? If so, any guesses as to what might be wrong with my car? Thanks.
 

·
Registered
Joined
·
12,249 Posts
Yes, you should be able to get cool air from the floor and defrost vents.

Even though you have the auto climate control features...you can also manually select air distribution (defrost/dash/floor) by using the 3 buttons along the left side of the IHKA control panel...and you can also take the blower off AUTO by pressing the fan speed button.

But if you have the IHKA on AUTO...but turn the stratified air dial all the way to BLUE...then only cooled air will blow from the dash vents. And if you have the IHKA temp set at 72° F...then yes, you could possibly well only get heated air from the floor and defrost vents because the temp sensor inside the IHKA control panel will do what it takes to maintain the temperature you have set.











 

Attachments

·
Registered
Joined
·
18 Posts
Discussion Starter #3
Thank you for your reply! Can you tell me under what conditions I should be able to get cold air from the floor and defrost vents? For example, I turned it all the way down to 60 degrees and there was still enough hot air blowing on Auto to make the car uncomfortably warm on a 50-degree, sunny day. Thanks again.
 

·
Registered
Joined
·
12,249 Posts
First try taking the system out of AUTO mode...then select the floor and defrost buttons (the top and bottom buttons on the left side). With this setting...you shouldn't get any air from the dash vents..so the stratified air dial setting shouldn't matter. All the air from the HVAC blower should be coming from the floor and defrost vents.

If you have the IHKA temperature set at 60° F...the air should also be coolish if the ambient temp is higher than 60°F. If the ambient air is lower than 60°f...then the air coming from the system will be warmer than the air temperture outside the vehicle. If you still want it cooler...then try turning on the AC (the snowflake) button which will turn on the compressor and dehumidify the air which should make it feel cooler. The AC compressor will run all the way down to 42° F.

If you are still getting hot or really warm air with the setting above...then you may have an issue with your water valve (aka heater valve)...which is a pretty common issue...especially since e38s are between 18- 24 yrs old. There are many threads about the water valve/heater valves and they are used on all the e38 generational cousins (the e46/e53) as well as newer BMWs...so there's lots of info on how to diagnose and fix them...as well as replace.

Good luck.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #6
This problem has been fixed. It turns out some previous owner removed the fuse for the auxiliary water pump. Once the fuse was replaced, the system works as it should. Now I'm wondering if the auxiliary water pump that I replaced 18 months ago is still good... :)
 

·
Registered
Joined
·
12,249 Posts
Wow...a fuse was the culprit? Thanks for posting back with an update...and I'm glad you were able to get things resolved. :thumbup:
 
1 - 8 of 8 Posts
Top