looking to add a manual switch to the low speed fans so it can be controlled while slow speed 4 wheeling where can i find the wire ? under the fan relays looks like there are 2 blue wires? or the wire number on the pcm thanks

 

my buddy did this on his truck. only thing is the way he did it caused a check engine light.

but im subing to see other ways how to

 

Are you wanting to be able to turn them off or manualy turn them on low?

 

Turn them on low with a switch

 

Pin 42 on the BLUE pcm connector is the one that controls the low speed fan. Splice into that wire and connect it to a simple 2 position switch, and the other side of the switch to any ground. Flipping the switch will turn it on, and it should still operate automatically otherwise.