heater blower not working

well the central locking has fixed itself today which is good but now the heater has stoped working i checked the fuse first and that is fine so i changed the heater fan complete with housing along with the relay that is attached to the side of it but still not working so then changed the control unit in the dash and STILL not working is there any other fuse's or relays that i have missed or anything else i should check.


however i have managed to get heat in the car i used the connection from the donor car and fitted a cigarette lighter plug on the other end and then plug this into the fan and the cigarette lighter and the fan works but only on full power so its either bloody hot or freezing cold


almost forgot its a 300tdi discovery 94 m reg

thanks chris

The speed control resistor pack for the fan is bolted to the heater ducting behind the glove box. It could be faulty but usually when it is the fan runs on full speed only.Possibly bad connections due to water dripping on it from leaks.
The slider switches also cause problems.
Have you got 12v at slider switch? if not suspect control relay.

funny you mention the slider switch as this had been messing about a bit the blower would just go off but if i just touched the slider switch it would come back on... i have changed this already and made no difference so will check voltage tomorrow and hopefully get it sorted

finally fixed it ... i went back over what i had checked/changed and could find nothing wrong so decided to take apart the heater control slider switch and found a very tiny spring that was suspposed to push switch onto the contacts but was not strong enough so i just stretched it and put it back together and plugged it in and hey presto heaters now working on all four speeds again

thanks everyone

chris