Climate control recirculation relay (Update and fix found)

[S.J.1981]

Hey guys,

i have been digging around to see why the recirculation flaps on my 1990 E30 are not activating, i have replaced the AC/Recirculation switch a few months ago, but after removing the side trim from the glovebox, i can clearly see that both passenger and driver's side motors do not engage when the recirc button is depressed.

The fans come on at low speed when i do that, according to the manual this is normal. I dug my hand in small spaces behind the radio, i can confirm that all the rods or cables are tightly attached to the motors.

Basically, what i can tell, without properly testing via volt meter, both motors are either dead, or not receiving power.

According to the parts diagram, there is also a relay behind the control panel.

My question is, has anyone replaced that relay? or had a similar experience? i shall attempt to disconnect one of the motors and check for 12v (or any voltage) in the wires, as well as feed 5v or 12v directly to the motor to see if they move/activate. But the relay is really hard to find, at least for me (either mine is missing or dug in deep that i can not reach).

[S.J.1981]

Well, looks like i need to start removing a lot of items to get into behind the climate control panel, to verify that the relais are actually in there. I searched online for pictures, i could not find any of the whole climate control unit revealing those relais.

*Update: After a lot of searching and digging i found the workshop electrical manual regarding testing various climate control components, including the flap motors, their connections, relays and so on. If the weather is good, i shall go ahead and perform the tests as well as updating this thread with the procedure, diagrams and so on for anyone in the future experiencing this problem of the motor flaps/recirculation flaps not working.

[S.J.1981]

This has turned out to be a can of worms, someone has bypassed the blower controls by splicing two wires, forcing the flaps open at all times/disconnecting their power flow. Also found another black/violet wire that has a splice in it, need to investigate further into this. Will be posting pics and details once finished.

[Victell]

Subscribed. Im having issues with my recirculation flaps as well.

[S.J.1981]

Subscribed. Im having issues with my recirculation flaps as well.

I doubt it would be similar to what i am experiencing. Someone literally cut off both relay harness, broke off the relays from their mounting points, spliced and bypassed all the green/brown wires used for power supply, motor flap relays as well as bypassing speed 1 blower yellow wires fat the AC/Recirculation switch and the list goes on. Basically, most likely one (or both) relays failed, or the blower resistor needs replacing, and someone did massive surgery there. I am following two electrical plans from the BMW workshop (one for blower control and one for recirculation flaps) and another diagram that shows the whole layout.

It is very....crappy work honestly, but i am doing my best to brings things back to factory, even got two OE relays that would be spade connected inplace.

[S.J.1981]

Small update:

The passenger side flap is broken, it would not remain closed even when pressed by hand. Which means one of the plastic parts that hold the metal rod to the motor is broken. Which also means, due to the lack of space, the HVAC would need to come out.

This is a good thing for me, since not only would i attempt to repair any broken plastic mechanical parts, but also have the whole harness for the HVAC system looked at, as well as take a look at the evaporator incase it is leaking.

I have already ordered both gaskets from the dealership, some colour correct and thickness wires and i have a bunch of AC o-rings that i ordered last year from BMW when i converted to R134a (i purchased around 8-10 of each o-ring).

Until the parts arrive, this is on hold, since it is a major job (dash out) but will update.

Seems someone gutted the relay system for the flap motors due to a broken flap....

[S.J.1981]

Well i found the problem, it was down to my fault as well as the system.

Basically my E30 is equipped with an automatic heater AND climate control regulator. In essence, the temperature knob is a small ECU, which uses temperature sensors from the blower housing (external temp), driver's side footwell (interior temp) as well as directly on the regulator itself (cabin temp).

This system does not have the typical relais found on NA E30 equipped with air conditioning from the factory (those silver relais found behind the entire front bezel). Instead, that ECU has a built in printrelay soldered onto the circuit board, pretty much like the SI batteries.

Thing is, there is constant power (always hot) running through that printrelay, as long as the ignition is on/engine is running. The only difference is when the recirculation button is depressed or not, that relay switches polarity to the flap motors (to open and to close).

I never knew this, and always assumed someone gutted the harness in my E30 and got rid of the relais (for some reason) and i started to fiddle with the system, when in reality it was indeed fine. That small ECU controls everything, from the heater valve (on or off) to the flap inside the HVAC box (to direct the blower air flow between the heater core or the evaporator electronically) to the compressor switch (on or off), evaporator temperature sensor to the main DME (to increase/decrease idle). The aux fan is bypassed completely, and the snowflake button sends a signal to the fan to kick in at speed 1.

This setup/option was never available (from factory) for North American models, however i shall post this incase someone has such a setup and requires help . Note, there was an option for automatic heater control and NO air conditioning as well, the small ECU did not contain the relays soldered inside, but the "standard" relays one usually finds according to my research.

First picture shows the "actuator" for the ECU how it controls the internal large flap to direct air flow between the heater core and/or the evaporator (cool/warm air or a mix of both depending on temperature setting).



Second picture shows how the flap motors are directly connected into the HVAC harness without exposed relais, if you look closely, the passenger side motor is double wired/bridged to the driver's side motor.



This is the ECU/Automatic Temperature regulator, which controls heat and climate control.



Here is the difference, the one on the left does not have the relais mounted, which use external relais, the one on the right shows the printrelais mounted.



This ECU costs €620 from BMW if you have the automatic heat AND climate control part number 64111386821

If you do have automatic heater control, but no relais inside (external relais) and whatever you set your temperature and nothing happens, this ECU would need to be either replaced (part number 64111386822 costs €782) or you can open it up and chase those resistors and circuit board and attempt to repair it yourself.

I found numerous posts on German forums, how people either installed this system (automatic heater and climate control) into their non-aircon E30s, or people converting from a "none auto" system to an automatic one.

Since those relais are small and constantly run hot (both heat and electrically), they eventually burn out. 12v is constantly flowing through them, and time, age, vibrations, heat etc will make them fail (like any relai).

Like the SI board batteries, one can replace those print relais with a new one.



This is an 8 pin F1C0012v relay from Takamiswa. One can find them from Radio Shack, or any electronics store.

[S.J.1981]

This shows a new print relai soldered in.





From the back:





Apparently this is another very common issue with this system, relais fail. Best method to test, is to apply 12v directly to the flap motors, if nothing happens switch the polarity around. If the motors respond and either open or close and you have this system installed in your E30, 99% it is due to burned out relais as discussed. Also make sure that the motors are connected to the flaps (check the metal arm) and be sure that there is no blockage or broken flaps (the flap pins break with age).

I ordered two of those relais, they run €2.22 here to have one as a spare. But this would save you €600+ from the dealership where the cause is a faulty printrelai running less than €3 and a few minutes of work.

I hope this helps out anyone with this system installed and is looking for a solution instead of a new ECU running €600+ from the dealership.

[fitswell]

this is really fantastic troubleshooting work.

my flaps seem to close *only* when the AC compressor is on. is this normal operation and if so, can I tie them to the switch directly?

[cory58]

Thank you S.J.1981 for another great thread. How did you determine that your car has the auto climate control. I've heard there is a small visual difference on the controls.

Cory

[S.J.1981]

this is really fantastic troubleshooting work.

my flaps seem to close *only* when the AC compressor is on. is this normal operation and if so, can I tie them to the switch directly?

It depends, are you in NA? then you could easily troubleshoot using the electrical diagram

Thank you S.J.1981 for another great thread. How did you determine that your car has the auto climate control. I've heard there is a small visual difference on the controls.

Cory

As you can see from the first picture, there is an electric motor (BMW calls it an actuator) on the right side of the climate control box. In Europe, there are two options, automatic heater and "standard" air-conditioning, then there is automatic heater AND air-conditioning. Basically that motor gets information from the small ECU (it basically receives signals from all three temperature sensors) and automatically adjusts the internal flap to determin how much heat to be allowed inside the cabin (same principal for the cooling). The flow direction (windshield, front vents and foot-well vents) also influence both heat and cooling depending on the sliders position.

If you are in NA, then you do not need to worry about this setup, it was fitted to European models only (as far as i can tell). Here in Germany, E30 owners adding climate control to their vehicles actually spending quite some money for this system (everything automatic), i have seen users on German forums spend as much as €1.500 for a while system (compressor, lines, box, harness etc etc).

[tfi_friday]

I hope this helps out anyone with this system installed and is looking for a solution instead of a new ECU running €600+ from the dealership.

Huge thanks for this write up. I had exactly this issue and the problem was that little relay in the control switch. My car sat unused for 3-4 years before I bought it and the flaps were stuck in the closed position, which meant steamed up windows any time I drove the car any distance.
I havent been able to source an exact relay yet, but I tried to give the relay a few small taps and it started working again as it should.

I'll probably replace the relay one I manage to find one.

Thanks again!