heater blower switch burns often

[alborz]

2010 Peterbilt 387
The heater blower switch which you change the speed of blower by turning it burns very often and the wire harness that plug into it discolored .
The blower resistor was replaced about two years ago.
Anyone has any idea or similar experience to share will be appreciated.

[Rawze]

(12-02-2018 )alborz Wrote:  2010 Peterbilt 387
The heater blower switch which you change the speed of blower by turning it burns very often and the wire harness that plug into it discolored .
The blower resistor was replaced about two years ago.
Anyone has any idea or similar experience to share will be appreciated.

Possible causes...

* The blower motor draweing too much current.

* The blower is not moving enough air, then overheating, then pulling too much current due to clogging of the core(s), filter clogged, or blower turbine slipping, etc.

* The fuses for the circuit have poor contact, allowing the voltage through to the circuit to drop, and the controller is trying to make it draw more current to speed it back up.

* The blower has been replaced with a higher current model.

Just some thoughts on it any ways.

[Waterloo]

I had the same problem a couple of months ago, it was a pinched wire under the dash... I fixed that section of wire and no more issues.

[dhirocz]

Mine was a crappy physical connection at the resistor. Cut the ends off, crimped, soldered and heat shrinked on new ends, and no more issue.

Also check the motor for excessive resistance in the motor as well as physical resistance. My motor was kind of hard to spin.

[Brock]

Peterbilt control units are bad for going out and insanely expensive! I paid $1380 CAD for mine.

[Rawze]

(12-05-2018 )Brock Wrote:  Peterbilt control units are bad for going out and insanely expensive! I paid $1380 CAD for mine.

for $1300 on a piece of electronics, I would be taking it apart and looking into replacing what was bad in it.