Dash A/C Fan Control

[BritFan]

Hi,
New to the Forum..

Have a 2004 National Tropi Cal 39' T396 Cat C7 350 HP.,

Need info on replacing the
Dash HVAC Fan Control. Fan runs on only one speed. Have had two techs confirm that the circuit board and fan work properly. They could't determine who supplied the control on the dash.

Need to replace the control switch. Need info on source, pt #, etc.

We use this unit in cold weather, need fan to run on high speed.

Marvin
2004 Tropi Cal
American Spirit 3 horse Trailer
Brittany Bird Dogs

Thanks

[Edw]

Dont know your specific controls but I had to replace the mixer valve on my Ford to shut off hot water to get cold AC. These guys also have the control knobs/dials
http://www.evanstempcon.com/serviceparts.php
Maybe this will help.

[SASman]

Marvin which speed is the fan running at; low, medium, or high? At what switch positions does the fan run? I had only 'high' speed in my car and determined that the blower motor was good so I replaced the switch. Still only one speed with the new switch. There was a diode in the blower motor circuit that prevents voltage feedback when using low and medium speeds that was burned out. The low and medium circuitry is bypassed when 'high' speed is selected and the fan ran only at high speed.
Good luck,
Steve