Transfer case actuator relay clicking 01 tacoma

My 2001 taco v6 automatic with auto locking front diff has the dreaded 4 weel high failure. I have read tons of posts on this so obviously have tried some simple suggestions such as checking fuses, tapping on the transfer case motor et. When I checked the 20 amp fuse it was burnt. Replaced it and now get a constant clicking sound from a relay behind the dash. Still no go when I push the button on the transfer case shifter. Going to try and get into the motor this wkend but doesn't look very promising as the screws are very corroded. Will also check the two switches on top of the transfer case as well. Previous owner says a new front diff motor was installed four months ago. Any advise on the constantly clicking relay?