My heater blower has packed up and I've searched the forum and found several threads re. heater problems, but I'm still confused.

Apparently, older Doblos suffer a common fault with the heater, which is the ballast resistor that provides the different fan-speeds. What's confusing me is that there is still voltage at the power plug to the fan, (although it's the same voltage for each fan speed - I would have expected each speed has a different voltage?)
The fan doesn't spin, yet it does if I connect it directly to the battery

I read somewhere that if the ballast resistor has gone, the fan will still work on max (no. 4), but my fan will not work at all. Anyone offer any advice?

Confusing, resistors limit the current so maybe although there is voltage there perhaps the current is too low to turn the motor, try a bulb. Speed 4 should work as its straight through but if a connector has corroded increasing the resistance it would affect all speeds.

Where can i find the resistor in my doblo cargo ??

Hi, and welcome,
it will be inside the FAN unit,
normally accessed under glove box,
Charlie