Background

The system was working OK but the air was not that cold.

The local garage recharged the system with their fully automatic machine.

On completion of this process, with the system fully charged, the fan blower decided to stop working.

When operating the up/down fan speed control, the bar graph display responds accordingly.

With the engine running and cold temperature set, the compressor is not engaging. Due to fan problem?

Unable to find a wiring diagram of the system. Controller part number:735451997.

Due the very low cost of these units on Ebay, circa £25, it is unlikely that they fail.

Work undertaken

• Testing the system using Multiecuscan gave blower fault B1919-14. Blower Module - Circuit Short To Ground Or Open.

• The blower motor was suspected and replaced. No fix. Same fault code present.

• Control wiring from the motor to the controller connector continuity tested. However, no data available to confirm correct connections. Confident that there are no wiring issues.

• There is a built in electronic speed controller in the fan. The speed is PWM from the controller.

• 12V DC present at the motor.

• ‘scope connected to the signal connections at the motor, no signals present.

• The controller was replaced by another unit with an identical part number. Still no fan operation! Same fault code present.

• Controller bar graph display still responds to up/down operation.

Discussion

As this motor problem was only present after a regas, does this mean:-

• Is there is an over pressure switch which inhibits compressor/blower fan operation for safety reasons? However, no codes are present.

• Incorrect code reporting of the blower fault?

• Does the Body Control Unit (BCU)/ECU have any control over the Climate Control system?

• Take the car back and get the system emptied then retest.

• Is there an under pressure inhibit switch which would negate the above test?

  Any suggestions for further work/tests? Thanks for your help in advance.