There isnt actually a relay for the switch per se, but if you would like i can send you the wiring diagram for the 4wd system.
Here you are,
Be sure to check those fuses...
If you have further questions on this, please feel free to reply.
Happy New Year!
Do you mean the pulse vacuum hublock solenoid?
How are you bypassing it?
Here is some good info for you to read.
I'll bet the problem is the GEM module is not activating the PVH solenoid..very common to fail.