I'm reworking my 5.3 harness and trying to eliminate everything I don't need in the engine harness, simply to make it cleaner and easier. I know a lot of people use the PCM to control when the fans cut on and off, but is there any reason to not just run them on a dual setpoint temp switch and bypass the PCM all together? I plan to do the same with the alternator by running a single-wire alt, and the a/c but just using a trinary switch and tapping into the factory request signal.

the only issue with the a/c i see is it won't cycle off the compressor at WOT, so i'll have to remember to do that before any pulls. any other issues, or input yall see with eliminating the above from PCM control?

 

I would ask the opposite question, why would you not want to use them? The fans and alternator are just too easy not to let the PCM control them because it's already set up for them. Why buy extra parts to do what the PCM will do for free?

The A/C is the only one that can be tricky, so I may bypass the PCM on that one depending on what year/engine you're running.

 

you have a valid point. after doing some thinking ive decided to keep the pcm control for the fans. the only reason i was going to go to a single wire alt is simplicity, and for options of new alternators, etc. however, we will see. the a/c crap is gone, im not even dealing with that nonsense. too much to deal with, ill just delete a/c completely if it comes down to it lol. but for now i plan to use the factory a/c signal, a trinary switch, a sanden compressor and the rest of the stock fox stuff