AC/Blower Motor issues

[Shankster]

Tried forum searches with no luck:

US version 95 540. Climate control panel has the 3 buttons, 3 dials and 3 levers.

System was discharged post storage. Had it evacuated and recharged with R134 last week.

Aux fan was dead so I took it out on the highway to test. AC ran fine (could feel the drag from the compressor) for a few minutes and then it cut out. The blower stops working on speeds 1, 2, 3. On speed 4, the blower works fine and blows ice cold.

However, the blower functions without a hiccup on all speeds without the ac engaged. I didnt realize this until today when the temps are close to 50F. Switched off the aircon and the blower functions perfectly on 1, 2 and 3. Switch the aircon back on and blower shuts off unless on speed 4.


Any assistance or pointers will be much appreciated.

[bbig119]

you need a new resistor control pack (https://www.autohausaz.com/search/product.aspx?sid=cb1d0445asyrbyv20aom2k55&makeid=800003@BMW&modelid=1012431@540I%20&year=1994&cid=resistor@resistor&gid=6557@Blower%20Motor%20Resistor/Regulator)

I had the exact same symptoms and this fixed the problem.

[bmwrp8]

you need a new resistor control pack (https://www.autohausaz.com/search/product.aspx?sid=cb1d0445asyrbyv20aom2k55&makeid=800003@BMW&modelid=1012431@540I%20&year=1994&cid=resistor@resistor&gid=6557@Blower%20Motor%20Resistor/Regulator)

I had the exact same symptoms and this fixed the problem.


I second that:D had the same symptoms too..but mine has the older "SWORD" type I didn't bought a new one just repaired it...cost me around $2;)

[bbig119]

I second that:D had the same symptoms too..but mine has the older "SWORD" type I didn't bought a new one just repaired it...cost me around $2;)

The replacement isn't anything complex, but I had a hard time getting the old one out. Its behind the console on the driver side. You have to really contort yourself to get at it and the clips holding it in are plastic and tight making it awkward to get them to release the old resistor pack. Being tall certainly contributed greatly to my difficulty as I ended up asking my shorter friend to do it and he seemed to have less problem.

All in all, it shouldn't take more than 5 minutes.

[Claude]

Tried forum searches with no luck:

US version 95 540. Climate control panel has the 3 buttons, 3 dials and 3 levers.

System was discharged post storage. Had it evacuated and recharged with R134 last week.

Aux fan was dead so I took it out on the highway to test. AC ran fine (could feel the drag from the compressor) for a few minutes and then it cut out. The blower stops working on speeds 1, 2, 3. On speed 4, the blower works fine and blows ice cold.

However, the blower functions without a hiccup on all speeds without the ac engaged. I didnt realize this until today when the temps are close to 50F. Switched off the aircon and the blower functions perfectly on 1, 2 and 3. Switch the aircon back on and blower shuts off unless on speed 4.


Any assistance or pointers will be much appreciated.

Rather strange behavier because there is no direct électrical interaction between the auxilliary fan an the blower motor. For sure the blower not working / or being intermittent on speed 1,2,3 is the symptom of bad blower speed control resistors, but A/C off and blower speeds 1,2,3 returning to normal operation conditions !! Can't see.... Have you ever replace the electronic A/C control module (under the dash) ?

[Shankster]

Never have. My wiring diagram reading skills are rather rusty so Bentley isnt much help too me just yet.

Local dealer has the resistor pack for $20. Figure i'll throw that at on, replace the microfilter and the blower motor (theres probably a mouse or something stuck in there) on the weekend and see if it helps resolve the problem.

Is there any electrical interaction b/w the blower motor and the compressor? Any kind of cutouts to protect against overload etc etc?



Rather strange behavier because there is no direct électrical interaction between the auxilliary fan an the blower motor. For sure the blower not working / or being intermittent on speed 1,2,3 is the symptom of bad blower speed control resistors, but A/C off and blower speeds 1,2,3 returning to normal operation conditions !! Can't see.... Have you ever replace the electronic A/C control module (under the dash) ?