If you're having problems with blower temp control or two speed fan not working properly try the following.
Remove the front courtesy light, then undo the 2 screws to remove the whole housing. Disconnect the orange plug which is for the cabin sensor. The heater then works by taking the mean average from the other 2 sensors ( coolant and outside ) and the first stage of the two speed fan should start to kick in at the right temp.
It cost me £63 for a main dealer diagnostic as an Autodata diagnostic won't pick it up. A new sensor costs £88, I got the whole unit from a scrappy for a fiver.( He thought it was just a courtesy light ! )
If this hasn't solved your problem, then follow the same procedure for the other sensors, but do the outside temp sensor first as the coolant sensor is on/around the thermostat housing.
Rob.
PS Mines a 1997 406 1.9GLX TD
406 Heater Problem / two speed fan - for info
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