Climate control unit power problem.. help!?

[gfowler]

Re: '96 328i

Recently, just in time for the hot season, my climate control unit developed a power problem. It shuts off for periods of time, then suddenly pops on again. But at least half the time, power's off.. fan, lights, everything.
Two years ago, I had a new blower motor & resistor installed, those should still be fine. Sometimes, I hear a knock or click which seems to come from the fuse/relay box in the engine compartment, just prior to the power popping on again. A local mechanic here pulled the unit last week & cleaned the contacts, they seemed a little dirty. We were hopeful, but the problem persists. He guessed it might need a whole new climate control module.. which I assume would be quite expensive. Would such a power/connection problem really be due to a bad control module? What other possibilies are there? Could the problem be a faulty relay?
Thanks!!

[Furious]

theres a chance of a faulty relay , has the mechanic swapped out the relay to check it? i suggest doing that above all else.

[SHAHAB323IS]

does the screen go dim at all, like dim screen and then the buttons don't work, and it'll shut on and off on it's own, if so you'll need to solder on a new capacitor on the circuit board, there's a really simple diy that i can post up for you if that is indeed the problem

[gfowler]

Not really a dim screen, it goes black completely.. all power off. It then pops back on at times. But more than half the time, it cuts off, no power or lights.

As for the relay, I'll pass that onto the mechanic. Last week, he fooled around with it, after I mentioned the possibility. I thought I saw him switch out that relay with one of the others, as a test, which didn't solve the problem. But would that be a good test? (In other words, are all of the relays in there alike, or is this relay (for the climate control unit) a special one that has to be tested with another of the same kind..) ? Sorry I don't know much here, I'm trying to find any other possibility, to avoid replacing the whole control board/module, which I'm not even sure would cause this kind of problem.