Climate control failure

[Joblack]

Hello all,
I have a 2003 z4 with a failing climate control unit. We had a specialist shop replace it and the used replacement also doesn’t work. On start up, the fan sometimes runs for a couple of seconds and shuts off. Usually the knob lights are out but sometimes one may be illuminated. By chance would anyone have any tips on how to diagnose one of these? Any tips on what to look for would be greatly appreciated as it is hard to drive in the colder months without a fan to keep the windshield from fogging.

 

[bigwinn]

I’m no expert but it sounds like the problem is not with the unit itself?

When the replacement unit was changed was it recoded as I believe they need action on INPA to get them registered to the car- not sure if that would just replicate the previous issue?

Can you pop some pics up?

 

[Joblack]

Here is a photo of the climate control unit. The shop that replaced it is a shop who specializes in repairing BMW’s so I trust they would have properly programmed it. I don’t think the issue is the climate control module, I think it may relate to one of the car’s sensors, wiring, or data bus. I am new to working on BMW’s so any troubleshooting advice would be appreciated 8)

 

[malc24]

Hi Jo, These switch units cost £500 plus new & so unless you have been charged that sort of figure they have fired a used one which may be faulty. I fitted a used one bought from EBay for £100 & no coding was needed. The symptoms were different on my car, the heater was stuck on hot. Was not that difficult to fit but centre vent & radio have to be removed to get it out from rear of dash. Maybe try returning to the repairer that fitted it as they should have fixed it the first time.

 

[malc24]

I mean they probably fitted a duff used one - damn autocorrect.

 

[Joblack]

What is strange about it is that this morning it appeared to work for the first 2 minutes of my drive. Usually it just blows air for a couple seconds on start up and occasionally pops on for a second or two while driving. I suspect a bad connection somewhere. I have the radio out as the amp doesn’t work due to water in the trunk destroying the amp years ago. The centre dash vent is also out currently so I could look for any signs of damage to the wire harness. That is good to know that you didn’t need to program anything when you replaced yours. I know that the climate control system has a lot to it. I am hoping to find information on connectors that I can disconnect and then meter resistance values of sensors to find if one is causing the failure.