99 Fans will not come on

What else can I check besides the relay, fuse and fans? Is there a switch/sensor or is it computer controlled? What do I need to do to get the shroud out?

Use a 12 volt test light check for 12 volt to the fan plug. If you have 12 volt
hook up the test light end end to positive terminal check if it lights when you touch the positive terminal.
If you have both a ground and power use a small hammer and tap the motor if it starts buy a new motor.
If you have no ground you can hook up a temporary so you can drive. Go to
http://www.alldata.com/ and buy a years subscription. They have good wiring diagrams. On some systems the computer completes the ground.
You need a wiring diagram before spending this amount of money.
No power make sure the relay pulses. A lot of problems are corrision under the relay base.
Normally the schroud bolts on use a ratchet and correct size socket. Normally 4 bolts.