Z4 3.0si A/C Not Blowing Cold

JoshW · Post by **JoshW** » Mon Apr 10, 2017 11:22 am

Hi Guys,

I have an 06 Z4C and have noticed that the A/C doesn't blow cold. When pressing the frost button I can hear something electrical change by the switches, but no noise of the A/C compressor clutch engaging. I have checked when the A/C is turned on, under the bonnet, and the compressor clutch doesn't appear to be spinning (not that I can see anyway). Have checked fuse 22 & 29 as they are for the A/C I believe, and they are fine. From what I understand the car isn't in transport mode either as the blower fans work fine, as well as the rear screen heater and heated seats. I've not yet had the pressure tested in the A/C system, but I assumed the A/C compressor would still engage?

What could be the problem?

Thanks,
Josh

Connexie · Post by **Connexie** » Mon Apr 10, 2017 12:27 pm

Suppose you are sure the AC system is not empty? In my case the control unit in the dash failed and had to be replaced. Not cheap, but can be found used. Some coding needed to get a replacement working.

Behr · Post by **Behr** » Mon Apr 10, 2017 12:38 pm

If you have access to DIS then it's easy to review the IHKA module settings and see the live status of various AC components. This may give you more of a clue what's going on with the AC.

Aside from Transport Mode, there are also K bus errors that can effect AC operation even if there's not anything wrong with the AC itself. DIS would help you understand what, if any, issues there are in that regard.

Short answer is to get stuck into some further diagnosis.

Rufus59 · Post by **Rufus59** » Mon Apr 10, 2017 12:39 pm

AC clutch will not engage if there is insufficient pressure in the system. If it's lost pressure that would point to a leak somewhere in the system perhaps, I'd get it tested.

JoshW · Post by **JoshW** » Mon Apr 10, 2017 1:45 pm

I do have access to DIS, INPA and the usual BMW tools. Sadly I don't have a set of A/C gauges so I will have to have that checked at a garage, but I will spend some time diagnosing in DIS as suggested. I think I need to extend my knowledge with DIS a bit further as I'm not entirely sure on how to approach diagnosis with that, establishing whether transport mode was present was pretty easy but I'll do some reading.

Thanks guys, much appreciated

elevensies · Post by **elevensies** » Mon Apr 10, 2017 6:27 pm

i had same issue, car had gone into transport mode,
i had no rear heated window, and something else too, dealer cleared it 50 quid

Behr · Post by **Behr** » Mon Apr 10, 2017 6:28 pm

JoshW wrote: ↑Mon Apr 10, 2017 1:45 pm I do have access to DIS, INPA and the usual BMW tools. Sadly I don't have a set of A/C gauges so I will have to have that checked at a garage, but I will spend some time diagnosing in DIS as suggested. I think I need to extend my knowledge with DIS a bit further as I'm not entirely sure on how to approach diagnosis with that, establishing whether transport mode was present was pretty easy but I'll do some reading.

Thanks guys, much appreciated

Once you're into DIS, highlight the IHKA module by selecting it/turning it black. Then press something like "Control Unit Functions" at the bottom of the screen. You then have the option to view/activate inputs and outputs by selecting them. From memory you can see AC circuit pressure (mine sits at 10bar 'ish from memory). You can also see Evap temp, compressor status and all sorts of stuff.

Rufus59 · Post by **Rufus59** » Mon Apr 10, 2017 8:33 pm

^^ this

I bet you can see whether the clutch is engaged or not too. If it's lost pressure have it leak tested.

Player 1 · Post by **Player 1** » Tue Apr 11, 2017 5:34 pm

About 80% of the time we find one of the following applies for cars:

1 - If your A/C's been working and has slowly petered off or you haven't used it in a while and it's not working. It'll need the gas recovered, pressure tested for leaks then recharged.
2 - If your A/C has been working one day then the compressor isn't engaging the next, you most likely have a leak in the condenser as that's first point of contact for any wayward stones coming through the grill. Again, get it pressure tested with nitrogen to check for leaks.

Start with an R134A recovery (if there's gas still there) and a pressure test with nitrogen before anything

JoshW · Post by **JoshW** » Tue Apr 11, 2017 8:10 pm

Hi guys,

Did a check through INPA and DIS and have established that the pressure is 0 (if I am looking at the right value?). I tried activating the compressor but got a red warning in INPA, and it didn't seem to activate anyhow. I'm guessing the AC system has no refrigerant in, hence why the compressor isn't kicking in?

: inpa 3.png (41.59 KiB) Viewed 3191 times

: inpa 2.png (43.52 KiB) Viewed 3191 times

Rufus59 · Post by **Rufus59** » Thu Apr 13, 2017 8:29 pm

0 pressure would prevent the compressor from activiating. I'd take it to a garage and get it leak tested. Discount here for A/C refresh

http://www.hotukdeals.com/deals/air-con ... 663076?%2F

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