Not your typical blend door problem..

[Chuckaz]

After hours and hours of research and troubleshooting I have a question:

1998 4.0 xlt Manual HVAC

The original problem was that I did not have any heat. I took the actuator off and it was not turning when adjusting the temp knob. I went to the ford dealer and tried a brand new one and it did the same thing. I started digging through the wiring to see if there was anything obvious.

I found a pdf by 4 Seasons that gave me the pin out on the actuator plug and I tested it:
C
With the clip on top unplugged the plug pins 4 3 2 1
8 7 6 5

With actuator unplugged and testing with key on:
battery voltage on 7
ground on 8
continuity between 4 and 6
varying continuity between 3 and 4 / 3 and 6 depending on the knob position


With actuator plugged in and testing back side of plug
battery voltage between 7 and 8
Near battery voltage on 4, I do not have this when testing
Varying voltage on 3 as knob is turned

Now that I have found one problem I took the hvac controls out and found that the Grey and red wire on the temp control was rubbing against some metal and was chaffed but not cut.

Will this fry the actuator? Did I ruin the new ford unit by plugging it into the truck? What does the pin 4 voltage control?

Fuse 10 is still good by the way.

 

[SoNic67]

Well, there are like 10 different types of actuators. You have the manual A/C one I guess?
Yes, touching the metal can fry the actuator, depending of what those wires are.
I would buy another one from dealer and if replacing it does not change anything I think you can return it.

PS: I did try several Doorman actuators but none did work on my automatic ETAC system (they might be ok for others), only the Ford dealer one.