1990 A/C Diode Necessary?

I picked up a lot of great stuff at the JY yesterday. One of the items I grabbed is the wiring that contains the relay, diode, fan connector, & temp switch connector for the aux cooling fan (I do not have factory A/C or HD cooling package). I was looking through the FSM and it looks like I'd cut the diode out for a non A/C vehicle and splice the orange wire to the gray/blk tracer wire instead. This would directly connect the temp switch to the relay. Then I'd only need 2 inputs: Yellow (key on power), & red (constant power). Obviously I'd also need a ground for the relay. It's a 1990,4.0, ax-15. Am I correct?