BMW A/C question
 

I have a 2002 BMW M3 6MT with 93k.

I've been having an issue with my A/C: with the system on and the output selector set for the middle (in your face) position only, I get cold air out of the side vents and hot air out of the middle vents. If I switch to the top (windshield) vent, I only get hot air towards the windshield. If turn on both the bottom (foot) and middle (face) outputs, I get cold air out of the middle, and hot air from the foot outlet; by "hot" I mean hot.

Yes, the center dash dial selector is set to the proper position.

The refrigerant level is fine, and the fan and compressor seem to be kicking in when they're supposed to.

Engine temps are normal.

When I get cold air, it's cold, but I shouldn't be getting hot air from other vents at the same time.

I suspected it might be the final stage resistor, but from what I've read (and previous experience) a bad FSR affects fan speed or shuts the fan down altogether.

I'd posted this on bimmerforums, but the most helpful suggestion I got was to check the heat selector dial :rolleyes:

Sounds like the actuators have gone out of time, or one has broken. Do a search and see if there is a series of switches you can push to reset the mechanicals in the dash.

there should be heater shutoff valves which control the flow of hot water to the cores, one for the left, one for the right......i have seen them fail many times on bmw/mb's.....they are usually controlled by pulsating 12v to control the amount of flow iirc......but should Shut when they get 12v......

Thanks for the tip!

I did a search on heater control valve and came up with this post which seems to describe the problem to a "T"

I'll try replacing the valve and see what happens.

did you get your a/c sorted?

I've ordered a new heater control valve, I'll report back after I have it installed.

I replaced the valve this morning, and it indeed fixed the problem.

yea!!!! glad that's all it was :-)

Glad to hear that yo got it sorted. My 2002 530I has a similar issue. Can you give me more details of the repair? Where is the water valve located? Where did you source the valve, and the location of the fuse for this system?

Thanks I'm not at home for a few more days, so can't dig around on the car to locate these parts right now. Any help is welcome, thanks

Richard

+2

Where is this valve..?

Why aren't you driving the Ghia? Pretty darn nice out.

On the E46, it's under the airbox/MAF, next to the power steering reservoir.

Here's a writeup on how to do it: E46Fanatics - View Single Post - DIY: Water (Heater) Valve Replacement

I bought the valve from getBMWparts.com because Pelican didn't carry it - the valve for the M3 is different than a run-of-the-mill E46

It's too hot to drive the ghia. I was nice this morning (drove the '56 single cab to get SBUX) but right this minute it's too dam hot.

Thx for the link widebody, I'll check to see if I can find the fuse first. Then on to the water valve.

Cheers Richard