My 1985 Nissan 300ZX’s air condition blows cold, but it will only blow at the windshield, and the far left and far right vents. Doesn’t matter which mode I push. The car doesn’t cool down to well in Arizona with most of my cold air meeting the hot windshield. It doesn’t help that I have a dash cover that sorta blocks the defrost vents, though only barely. What I want to know is what to replace to fix the mode selection. Is there a relay, a switch somewhere, or is it the dash unit itself? I don’t think its hoses, but is that possible? If someone can point me in the right direction as to what parts I might need, that would be great.
I tried looking it up on google, and browsing eBay for A/C parts, and seeing if any sounded like this was their function, but no luck.