When I have ignition on and engine running, park or drive, I try and switch the elec. shift switch from 2w to 4w drive. Nothing happens, and I have no lights on dash indicating 2w,4wh,4wl. Any suggestions. I did check through fuses, but did not find any blown. I don't know which fuses the control would be through. The Hayes manual sucks, due to no schematics for 4x4 control.

 

Try checking your owners manual for the correct fuses

if you don't have one, a search here for manual would provide this URL
https://www.fleet.ford.com/maintenan...ls/default.asp

A quick check is to see if the shift solenoids on the firewall have power at the top of them. Don't use the ground on the bottom of them, that is switched by the GEM to make them work.

For the 4x2 one
+ 12 V in run position white w/ light blue stripe wire ( hot any time the truck has the key in the run position, direct wire to JB Fuse # 23. )
ground = gray w/ black stripe wire ( when GEM calls for it )

For the 4x4 one
+ 12 V in run position white w/ light blue stripe wire ( hot any time the truck has the key in the run position, direct wire to JB Fuse # 23. )
ground = red wire ( when GEM calls for it )

Fuses you need to check for 4x4 are
cab
Fuse #13 : Brake pedal position switch ( for 4Lo function )
Fuse # 23 : transfer case electric clutch relay & Center axle solenoids ( on firewall )

engine compartment
Fuse #17 : Transfer case shift relay module

Power to the 4x4 mode selector switch is from the MFS, dark blue wire on the switch.

When you try to shift into 4Lo, do you have the brake on ?