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MG ZR ZS ZT Technical - MG ZS heater question

Hi,my neighbours zs 120 internal fan/heater has stopped completely. It was working fine then only on fan speed 3/4. Now is won't work on any setting. I have checked other sites and they all say that if the resistor has packed up then 1/2 should work.
Any help for a great neighbour please.
Thanks Jamie
jamie

Hi Jamie,

My own ZS 120 has a problem with the heater/air-con fan switch. The first two switch positions do nothing at all but the third and fourth positions work fine.

This pehaps bears out the statement that 50% of the settings work.

It is something that I am happy to live with until the next service. No fan assistance at all is a different story.

Dave
Penwithian

It uses one of three different resistors for anything other than the fastest speed, that is direct mi.e. no resistor, so if not even that works I'd suspect a connection or other component. If you can't hear the air-mode motor as you switch between recirculate and fresh-air then check the fuse. If those are OK the resistor pack should be in the ducting for cooling, accessed by removing the glovebox and lower cover panel. Remove the connector and check for voltages on the four wires as you turn the control between the four on settings. If you don't see 12v on one or more then it is the switch or the supply to it that is faulty. With the connector refitted check the voltages again, this time they *should* be different according to what speed you are on - lower voltages with lower speed - *if* the motor is running or being powered. If they still all show 12v then its the heater fan motor or connections to it open-circuit. Different voltages but no blow probably means the motor is siezed, and that is likely to burn out the resistors, possibly blow the fuse.
Paul Hunt

Thanks for all your help. Paul many thanks and we will work through the system one evening. Thanks again
jamie

This thread was discussed between 12/07/2009 and 13/07/2009

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