Heater control unit malfunction.

[Wheelyneil]

Hi guys, I’ve been lurking around for a few days and there are clearly some very knowledgable people on this board. Hopefully one of them can shed some light on a problem with my sons ‘new’ 1.2 Polo

We recently fitted an Android based GPS head unit to replace the previously installed radio. However the heater and air-con control unit has stopped working. The back illumination doesn’t work, the air con and recirculate buttons don’t illuminate or operate. Essentially it’s dead. Is this likely just an unlucky coincidence or has connecting the (Chinese) head unit to the CANbus upset it in some way? All fuses are checked OK and the unit is getting 12v. None of the wiring Is damaged, and other than connecting the head unit to the existing radio connector no other wiring has been touched.

If the unit had failed, are there any compatibility issues with used replacement parts. All look very similar, but there appear to be numerous revision levels. Are there interchangeable or do they have to be programmed to the specific vehicle model?

Thanks in advance.

[iichel]

does the ac panel come back online when you disconnect the radio?

[Wheelyneil]

Sadly not, remains dead. I’ll try disconnecting battery and power cycling to see if that resets anything, unless you’d advise otherwise.

[ciclo]

If disconnecting the battery does not solve anything, a diagnosis would be helpful, a fault must have been stored in the gateway/air con, which must be cleared.

[amer6R]

try removing the headunit? Aka try it without the headunit

[jamiebooth]

Did this get fixed ? If so what was it? we have a similar issue with my sons car.