96 bronco EB 5.8
 

I picked up a 96 full size w/5.8 and the a/c system WORKS when power is bypassed, but its not powering up automatically w/switch. Is this more likely a relay or switch control...all fuses have been checked.
Also, there is a light clunk in the rear end, with 126k miles i understand this will have a few flaws but is there a common bushing/bearing/part that wears and can be repaired before it gets too loud / bad ??

I brought it to a mechanic prior to purchase but if I can DIY i prefer to, thanks !!!

thanks in advance, JB