09 Yaris Heater blower problem

[CTScott]

Originally Posted by motoxxx3

Just had a call from the dealer - they have found a bad earth. Apparently it is now fixed!
Let's see if they have!

That sounds plausible. With it happening under load, I would believe that a bad ground could cause that.

[motoxxx3]

Originally Posted by CTScott

That sounds plausible. With it happening under load, I would believe that a bad ground could cause that.

Latest update:
They have today fitted an auxillary earth strap from the blower motor to the car.
The reason being that they now think there is a fault with the earth wire in the car's multiplex wiring harness and by doing this is it will prove whether this is the case.
(They have changed every other component in the system)
I have to run the car for a few weeks and see if this has cured the problem.
Everything is checking out o.k. now with the voltage.
If this turns out to be the problem they are going to fit a complete new wiring harness.