2 speed fan question (renix)

getting ready to install a volvo 2 speed fan with volvo controller, i've searched and searched and the one question i have is using the 2 speed fan switch ECHFS151 in place of the stock fan swicth in the radiator bung. same thread pattern M22-1.5 so it should fit right?
i also have the HO thermostat housing that i could put a fan switch to turn on the the other fan which is off a 99.

a little backround on my rig,
89 laredo
4.0
aw4
closed system

99 fan has been wired to a switch by previous owner using a relay (not the stock relay)
my goal is to get everything to turn on without a switch because last summer i forgot to turn the switch on a few times and it gets pretty hot here (Bakersfield, Ca.) in the summer with plenty of days over 100*
using a swicth just to turn the fans off for water crossings.

anyone use a set up like this, any input would be awesome
thanks
Larry

Larry, I think you are on the right track if you want to keep it electric. Honest to god, though - a mechanical fan clutch, if you have the parts on hand, is cheaper easier & moves as much or more air than any electric setup.
If you don't...
Yeah, if the fan switch will thread into your radiator - go for it.