Blower Motor PWM Upgrade
Posted: 13 Apr 2021, 21:54
I had been putting this job off for a while but has Easter week off so managed to get the dash out without much hassle. The heater box on the other hand did not want to come willingly. One screw seized and I eventually cut it's head off and had to drill what was left of it out. Anyway.
My blower motor has stopped working so I had a replacement ready to fit and the brickwerks foam kit for the heater box. I also had a PWM (Pulse Width Modulation) controller intended to replace the resistors used for the fan speed control. I was getting annoyed so was planning on leaving the resistors in until I opened the box
The resistor pack must have got pretty hot. It also charred some of the earth wires
So out with the resistors and in with the PWM controller. It fitted very neatly to where the resistor pack was previously located so I mounted it and wired it up. I hope I don't live to regret this placement. I was able to use the existing wiring harness and insert the PWM without much bother. The control knob required three wires so I just used the resistor wires. They aren't going to be carrying any load so are over rated for this purpose but why not use what is to hand.
Bench tested and all working as it should be.
Between stripping the box, removing all the old adhesive, cleaning, fitting new foam, wiring in the PWM and reassembling it took me a full day.
I have modified my heater control panel so that the original control knob can still be used, rather than it be redundant and another knob mounted alongside. I will take some pictures at the weekend when it will hopefully go back into the van
My blower motor has stopped working so I had a replacement ready to fit and the brickwerks foam kit for the heater box. I also had a PWM (Pulse Width Modulation) controller intended to replace the resistors used for the fan speed control. I was getting annoyed so was planning on leaving the resistors in until I opened the box
The resistor pack must have got pretty hot. It also charred some of the earth wires
So out with the resistors and in with the PWM controller. It fitted very neatly to where the resistor pack was previously located so I mounted it and wired it up. I hope I don't live to regret this placement. I was able to use the existing wiring harness and insert the PWM without much bother. The control knob required three wires so I just used the resistor wires. They aren't going to be carrying any load so are over rated for this purpose but why not use what is to hand.
Bench tested and all working as it should be.
Between stripping the box, removing all the old adhesive, cleaning, fitting new foam, wiring in the PWM and reassembling it took me a full day.
I have modified my heater control panel so that the original control knob can still be used, rather than it be redundant and another knob mounted alongside. I will take some pictures at the weekend when it will hopefully go back into the van