s40 heater not working
 

hi i,m new at this so be kind: s40 auto (w) plate, heater not working, main fuse ok, power to all other fuses ect inside/under bonnet. is there a in line fuse some where???????????/

no airflow or no heat ?
 

Hi M I,

Firstly welcome to the forum.. When you say the heater isnt working, do you mean the fan/blower isnt blowing air out of the vents, or do you have air blowing out but no heat in it?

If its the blower not working, i recall theres a regulator i think some refer to it as a 'transistor', but its basically a device on a heatsink (aluminium finned thing) thats in the passenger footwell (above it i seem to remember) i had mine fail on my old S40 resulting in slow or no fan speed, not sure if this applies to all aircon systems, (mine had the full A/C option) but i would think so if yours has a fan speed control knob. Ill dig out some more details, if this sounds like your problem.

heater not working
 

no blower working at all

Check the transisitor module
 

Sounds like the module i mentioned,, the blower has a +12v (fused) feed to one side and then then 'transistor' is used on the return side to chassis to control the speed of the blower, if you remove the passenger well plastic cover (above passengers feet area) then i think the module is there on the left side, connects via a 4pin connector, if you want to test out if its the blower thats faulty or the transistor you can (if you get the correct connection) link the blower return side to chassis, which should result in the fan working at full speed. If the blower doesnt run or it pops a fuse then its probably the blower thats faulty, but i think the transistor is usually the culprit.(might also be a quick temporary fix if you use a switch in this side) the module P/N i think is 30864189. Ive got some notes i could email if you want to pm me your email add, hope thats helpful.