I have a 2001 Accord 4 cyl. VP. Lately, the climate control buttons (and functions) have been shutting off intermittently. Today, I think the unit finally died. Only the the fan and temperature knobs still work. After several hours of internet searching, I think I found the correct replacement part - a heater control assembly. How difficult is it to replace, and what repair manual(s) can you recommend?

Thanks