88 760 Intermittent Climate Control

[88760RICH]

My A/C and blower fan completely fails to work sporatically for days, but then works fine for days at a time. I bought a Grey Stribel A/C Relay ( see photo) from an online source, but cannot find it in my normal relay panel ( see photo ) behind shifter on passenger's side. Is this relay incorrect for my car ? Or if it is correct, where is it located ? When the problem occurs the illumination light surrounding the A/C Button continually blinks. While it is blinking I have completely unplugged the black control unit located behing glovebox ,above evaporator housing ( see photo )...and the blinking continues uninterrupted. I just installed a reconditioned A/C Control Head / Switch Panel which has not solved the problem. I am leaning toward the black control module. Can anyone support my conclusions ? Any sources for good used part ? Thanks for any feedback.