I'm intent on doing the manual to eatc swap but I've got a few quick questions. Hopefully an electrical expert will chime in. I know that the a/c demand pin needs to be removed from the larger plug in operating my manual unit. It will need to go to the smaller of the two plug ins on the back of the eatc unit. This is the "ubp bus" signal from the cluster. Now, what's the difference between the a/c demand signal going to the manual unit and the ubp bus signal required for the eatc unit? Secondly, I know I need to enlarge the hole in the evap. case for the speed controller, but, I'd rather avoid it if I can. Can I just use a lead from the manual resistor -like the high speed signal- and use that as the signal for the eatc unit? Is the ubp bus signal simply used to power off the eatc unit? I did plug in the eatc unit the other day and everything worked except the unit would not power off and the fan speed could not be increased. With the 2 questions/ideas mentioned above, can I make this an easier swap? Any help is appreciated.
-I did try searching, but the threads are older and don't mention my questions.

 

I personally have never attemted this job..
I know there are several differences with part #'s, harnesses, input sensors, etc..
Are you looking to attempt this on the 04 F-150 in your pic?

 

Yes, that's my truck in the sig, the "test" vehicle. I've checked the harness differences in the workshop manual in oasis and I can take care of the other issues (or so I think). The main questions I've got are regarding the ubp bus signal with the cluster ( I tried calling the cluster exchange centers but they couldn't help) and the speed controller. I'm thinking the speed controller is more of a sensor signal indicating the blower motor is on vs. just a signal feed and that I'll probably end up enlarging the resistor hole to fit the speed controller. I did find that a 09 F150 speed controller is closer in size and the plug in is the same as my 04 resistor plug. No hacking required there. We'll see. All that really leaves is the a/c demand wire from the cluster in connector 220a for manual a/c vs. the ubp bus wire in 220b for eatc. I can deal without the temp sensor for now and manually adust the control head temp. as required and steering wheel controls aren't necessary.
Can you jump onto FMCDealer and look at the harness layouts for me?

 

What about this? Found it in the workshop manual.
The ambient temperature sensor signal is received by the instrument cluster module which communicates it to the EATC module via the vehicles UBP network.
CKT 470 (PK/BK) in-vehicle temperature sensor return
Does it mean I don't need this signal wire?

 

May have to look into that for you... send me a pm with your email address..

 

this forum takes care of your a/c demand questions
https://www.f150online.com/forums/20...e-control.html