Cruise Control not activating

Here is one test, you should be able to scan through the balance of the Cruise control system on this site.

https://charm.li/Toyota/2001/Tacoma Extra Cab 4WD V6-3.4L (5VZ-FE)/Repair and Diagnosis/Cruise Control/Testing and Inspection/Initial Inspection and Diagnostic Overview/Indicator Check/

 

Unfortunately I have a 2004 which has a different configuration so I can't test out my hypothesis but it looks like the cable that comes from the passenger side looks loose/stretched. I would tighten it up using those adjustable nuts where it attaches to the throttle body and see if that gets you anywhere. I'm not sure which cable is which. You can figure out which is which by disconnecting one of the cables and turning on the car in park and pressing the gas pedal. If you rev the engine whichever one is connected is for the throttle and the other is for the cruise. Or oppositely if nothing happens you disconnected the throttle cable.