Technical Blower motor on all the time

[Saltpeter]

Ducato 2.3 130 multijet 2007. Trouble again with the blower motor. It stopped working and I replaced the switch and all was ok for a while. Now the blower comes on with full with the ignition and the switch does nothing. Looked everywhere for help but normally it is the switch broken or the resistor pack but the switch is nearly new and the resistor pack checked out OK.
Help please!

 

[varesecrazy]

Ducato 2.3 130 multijet 2007. Trouble again with the blower motor. It stopped working and I replaced the switch and all was ok for a while. Now the blower comes on with full with the ignition and the switch does nothing. Looked everywhere for help but normally it is the switch broken or the resistor pack but the switch is nearly new and the resistor pack checked out OK.
Help please!

Electrics..

On the punto poeple say the EARTH is switched.. maybe you have a bad earth at the resistor.. (or switch)

So it has no dropping ( or switching) effect.. just full battery voltage

 

[Anthony489]

Hi Saltpeter

See the schematic attached. The blower motor N085 gets a live feed (red wire) via Fuse F08 (40A) and Relay T08. The "earthy" end of the fan (black wire) is switched directly to ground C016 by the speed switch H081 on full speed, and via one or more of the resistors in O030 for the intermediate speeds.

If your vehicle has air conditioning, the "earthy" end of the fan is also connected to the air conditioning control board H080 via a black/violet wire from the junction point at pin 5 of the resistor pack. This allows the A/C to override the fan speed setting if necessary.

I suggest you check for short circuits to ground in the earthy side of the fan.

 

[Saltpeter]

Thanks Anthony 489 and varesecrazy, I didn't realise it was the earth which is switched! Seems a bit odd but it is a Ducato...........

 

[varesecrazy]

Do let us know what you find