I know, fan speed question

[mbrummal]

The 'resistor" is actually a transistor module. Check the voltages coming out of the known good ATC on the green wire on pin C0793-1 with the transistor module removed. If it is ok, the problem is the transistor module. If it's still bad, it is likely a wiring problem between the ATC and the transistor module.

 

[Grum.man]

After hours of chasing wires and testing voltage and checking grounds I finally took a long shot and pulled the resistor out of the 04 and plugged it into my 03. Low and behold it worked. Somehow I've managed to get two bad new resistors from two different companies. Luckily I saved the box this time and AB is sending me another one.

 

[Grum.man]

Well the plot thickens. Got another resistor pack from AB that did not solve the problem. Found a 2000 model disco parts truck locally and tried one of my resistors on that truck and it worked. Pulled the ATC from that truck and installed it in mine with the same resistor and it doesn't work. If I plug my resistor into an 04, it doesn't work. If I use the 04 resistor it does work but doesn't physically fit into my early vin 03 blower housing. Not sure what the root cause is but seems my only resolution is to swap an later vin 03/04 blower housing and resistor into my early vin 03.

 

[Grum.man]

While the why still alludes me, I have successfully transplanted an 04 blower housing into my early vin 03 so that I can use the later style resistor and now have a fully functioning climate control.