AC issues - United Bimmer Community

**msr01908** · 07-19-2011, 09:09 AM

Morning,
I have searched for an answer to this problem since last year. The local repair shops are unsure of any fixes, so i thought i would put it out here on the forum.
I have a 94 325i convertible, with a dual ac system (different temp settings for passenger and driver). It is the analog (dial) system. When I place the air flow indicator on the footwell setting, air comes out toward the feet and toward the windshield (defrost). The trouble is that the air coming out of the passenger side is at full heat, no matter where the temp is set. If I use the dash setting for airflow, the temp is right. I assume there must be a mixing valve or ?, but i have no idea where to look. One shop said it required taking the entire dash apart to get to it, but even then, they were not sure that this would fix the problem.
Any ideas or suggestions will be greatly appreciated.
Thanks

**Manolito** · 07-19-2011, 10:19 AM

I have the opposite problem on a '97. Hot air blows out in the driver footwell, even when the A/C is on.

I presume that one side of the heater control valve has failed. The heater control valve is under the hood near the brake master cylinder.

I want to be sure that this is the problem before spending $225 on a heater control valve because I have to pull the air plenum off the firewall to get to the hoses on the heater valve. I replaced the heater hoses on my other '97 and it is a PITA. If I have to do this heater valve, I will obviously replace ALL my heater hoses while I am in there.

When I get time, I will take a voltmeter and try to figure out how the heater control signals the heater control valve. Then I can create a signal, or cross the wires, to see if the problem is the valve or the heater control.

**3050rpm** · 07-20-2011, 07:13 AM

While I tend to think the problem does lie with the heater valve, I'll just toss this out for consideration, the a/c computer could be at fault, but don't panic, the fix could be comparatively simple. Check this site out to see what it has to offer http://www.macadamizer.com/bmwfix.html

**msr01908** · 07-22-2011, 09:51 AM

Thanks, I will take a look at the control valve as soon as this heat wave passes. While the fix for the digital control unit seems simple enough, is there a similar solution for the analog (dials) unit?

**3050rpm** · 07-23-2011, 09:38 AM

I rather doubt there'd be much if any difference between digital and analog versions at the circuit board level, seems to me that the only difference is the display of the temperature setting on the faceboard, so the fix would seem to apply to both versions, if indeed that is the problem in this case.

**Digitalman2112** · 11-25-2012, 10:27 AM

Hello. Was there every a resolution to the issue? I'm experiencing the same thing and would love to know where the issue lied on your problem.

Thanks,
Dman2112

DEATH2000 · 12-02-2012, 12:56 AM

Quote:

Originally Posted by Digitalman2112

Hello. Was there every a resolution to the issue? I'm experiencing the same thing and would love to know where the issue lied on your problem.

Thanks,
Dman2112

The blend door actuator may be the issue and need replacing.