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milton6x 04-08-2019 05:24 PM

Help , please , no AC
I took my 2007 Z4 coupe out of hibernation today and found the AC is not working . Fan is running but no LED showing when pressing the snow flake button or window button . I checked AC fuses 22 and 29 in the cab and found them to be good . I found the under the hood fuse panel but find no labels for the fuses . Cannot get the under hood fuse box cover all the way off with out some more violence . Poorly located . Any ideas what the next step should be ?

Rob2m 04-08-2019 10:49 PM

Move to the UK, you will only miss it 2 days a year then!

Sorry cant help.

papitosabe 04-08-2019 11:57 PM

Was the battery dead or did you remove the battery? It may be in what's called "transport mode." You can get it out of that mode at dealership for like which will probably charge you $100 plus for 5 mins of work. Or get the software on ebay I believe but iirc you need a windows 7 or vista pc.. I think it's called DIS something. Or check craigslist for a bmw tech that will program it. A guy quoted me $45 just the other day...might be able to talk down for $25.

Doug Huffman 04-09-2019 02:33 AM

Here's an IHKA schematic wiring diagram, but the HVAC system is so far from voltage supply that fuses aren't even part of the system shown. At the top of the page are link URL to higher menus.

wifesauto 04-09-2019 05:20 AM

some systems will not let the compressor run if it is low on refrigerant

Doug Huffman 04-09-2019 06:05 AM


Originally Posted by wifesauto (Post 12966399)
some systems will not let the compressor run if it is low on refrigerant

Pressure Sensor via Junction Box
The refrigerant pressure input signal is a direct junction box input signal and is relayed to the IHKA via the K-CAN. The IHKA requests actuation of the auxiliary blower by the DME (ECM) depending on the refrigerant pressure.
The IHKA determines the relevant A/C compressor load torque on the basis of the input signals from the pressure sensor and the compressor speed. The DME (ECM) control units are notified of the load torques by the IHKA and used by the DME (ECM) as input variables for actuating the electric fan. [Notice: Blower =!= fan]

A/C Compressor Control
The IHKA is the master for controlling the A/C compressor. Pressing the AC button on the air conditioning system operating unit switches the air conditioning system to the ready state.The IHKA transmits a speed increase request to the DME (ECM).
Depending on the temperature and the nominal-value setting, the IHKA sends a cooling power request to the DME (ECM) If the DME (ECM) is ready and in a position to provide a torque of > 20 Nm, the DME (ECM) issues a release for a load connection of up to 30 Nm. This release is also monitored by the junction box. The IHKA issues a command to the junction box to couple the connection. The junction box returns the coupling status to the DME (ECM)
The compressor output is controlled by the IHKA control unit by means of an infinitely variable control valve. The IHKA control command is converted into infinitely variable proportional powering of the control valve in the junction box.
The control is designed as "sliding evaporator control".
The evaporator temperature is controlled to a value of between 2C and 8C depending on the cooling power request. The temperature sensor signal in the evaporator is used as a feedback signal to the IHKA control unit. The coolant request is limited by the potential evaporating power of the evaporator.
The evaporator is prevented from icing up by controlling the compressor output (appropriate reduction).
In order to reduce CO2 emission, avoid unstable conditions when the engine is idling and for full load acceleration the DME can activate a compressor shut-off via the junction box. If appropriate parameters are present, the solenoid coupling of the compressor is opened.

wifesauto 04-09-2019 06:13 AM

mechanics short version......check fuses/put gauges on system ............mechanics were needed cuz engineers couldn't get it right the first time

milton6x 04-09-2019 06:35 AM

Thank you ,
Thanks for the responses . I am overwhelmed with life's complications right now , but when I can get back to it , I will check the under hood fuses more thoroughly . Car did have a Battery Tender in place all winter . If it is more complicated than fuses , it is off too the heartless dealer with my SS check in hand .

wifesauto 04-09-2019 06:44 AM

a local shop should be able to re-charge if that is the issue and look for leaks

ShakyDog 04-09-2019 06:55 AM

Does everything else work? Does the rear defroster? If not then I would bet your car went into Transport Mode.


milton6x 04-09-2019 07:39 AM

The rear defroster is not working . Transport Mode must have been triggered . Leave it to BMW to over complicate everything . Thanks ,

Doug Huffman 04-09-2019 08:16 AM

Heated rear window may be supplied by 30 Amp fuse F20 in power distribution box A41 behind passenger's dashboard. It may be controlled by relay K13 in A41, in turn powered by 5 Amp fuse F25 in A41 and controlled by IHKA A11a.

janole 04-10-2019 10:20 AM

Transportation mode for sure this has happened to me before and the exact same things didn't work, unplug battery, wait at least 30 mins with the trunk lid open, re-connect and it should be good to go. When ever you do anything to the battery, tender, charge it, change it, always wait 20 mins after you open any door or trunk lid so the system can go into sleep mode before you plug or un-plug anything into the electrical system

milton6x 04-10-2019 12:30 PM

I will give it a try . Thanks ,

milton6x 04-16-2019 04:22 PM

I tried the thirty minutes with the battery disconnected and still no AC .

ShakyDog 04-17-2019 08:42 AM

It is a setting that must be changed with a programmer (or taken to the dealer to reset). I have never heard of the battery disconnect removing it, I do know that is what causes the issue.


milton6x 04-17-2019 09:13 AM

Thank You ShakyDog , The BMW seems to be designed around supporting dealerships , not customer support . Full of unneeded , unwanted quirky electronics .

papitosabe 04-17-2019 09:56 AM

Great write up if you can get someone off CL with the sw.. doubt they would need instruction, but mention you know it takes a couple of minutes..

janole 04-17-2019 02:55 PM

To offer more details in my case, because it did actually work, but I have no idea why.

The battery had run low to a point where it would not turn over the car, radio and lights still worked, just the clicking sound of starter, so I put a trickle charger on it for about 6 hours, and it started right up, went out for a 30 min drive and noticed I had no AC, no radio, maybe other things, I didn't check. Parked the car and started to worry. Next morning went out to try it again, car was absolutely dead, no nothing, no dash lights, nothing, but I get out of the car and there is a sound like something is running in the back (fuel pump?). Weird So I pulled the battery out of the car and put it on a real 20a charger overnight, re-installed it. Started up, and everything works, Alternator is charging at 13.7-13.9 and I have not had an issue since, that was month and half ago.

milton6x 04-17-2019 04:51 PM

I had a Battery Tender on the stored vehicle all winter and the battery turned the engine over easily . I do not know what triggered the "shipping mode". Car was stored under the same conditions the winter before with no problems .

Andyz4 04-19-2019 11:05 PM

Milton, does your HVAC blower operate at a very slow speed (only)? If so, you are likely in transport mode. Along with no ac you will also have no radiator fan when you switch on the ac. If you dont have software dealership can clear it for the cost of diagnostic. If blower is working at all speeds, you are likely just low on freon.

milton6x 04-20-2019 09:22 PM

All the symptoms match . I will be bringing it to a dealer when time allows . Thank You ,

lmacmil 05-07-2019 10:12 AM


Originally Posted by wifesauto (Post 12966473)
a local shop should be able to re-charge if that is the issue and look for leaks

There are at least 2 videos on YouTube showing a DIY recharge for the Z4. Looks pretty straightforward. Going to try it myself when it's consistently above 70. My AC quit last summer but never bothered to recharge it since the car spends 90% of its time with the top down.

milton6x 05-25-2019 11:49 AM

I took the Z4 to an independent BMW-MB garage , they canceled out the shipping mode for free . But made up the loss by charging $306 for a new battery and initializing . Thanks for all the suggestions .

janole 05-25-2019 12:18 PM

Glad you got it sorted, $306 is a lot for a battery, but I've paid more for less on dealer repairs
FYI there is no initialization needed for batteries on the E85/E86

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