Apparently common problem with heater

**Bob France** · Wednesday 26th October 2016, 10:32

Hi all,
Had smoke appear at the top interior vent of my 850 R,changed the fan,( definitely working) changed 2 resistors( in case) and have now changed the main control panel box,still not working.Symptoms are,when I start the heater the fan will run for maybe one or two seconds then nothing.Also,when I changed one of the resistors it ran at full speed as soon as I turned the key with no control at all,Anybody had the same problem?,I thought it might need the Ecu resetting but before I go to a stealership I hoped there might be another thing I have missed,any help appreciated,
Thanks Bob

**woz** · Wednesday 26th October 2016, 16:56

DEfinitely smoke is it then Bob? Not steam like when a heater matrix has gone - that will only happen when the engine is warmed up and wouldn't affect your fan not running when it should. Guess you would have found that out when you had the fan out anyway, with coolant under the carpet etc. Just thinking it may be two issues not one. W:>)

**Bob France** · Wednesday 26th October 2016, 21:18

Hi Woz,no definitely a wisp of smoke from the centre top vent and a smell of electrical burning,but I smelt the pcbs on both the head unit and the resistor but they didn't seem or appear( when I looked) burnt.
I have changed the three main components but no joy,when I start up the head unit flashes for about 10 seconds and then has one light one like normal,however if I try to start the fan,it will run for maybe one or two seconds only.I have tested the fan with a permanent live and it's good,the resistor is the third one I have tried so I assume that one has to work and now I have tried a new head unit but it's virtually the same as when it broke down.Have I missed something?.