Time Sensative Blower Help?

[Jehu]

My heater blower I've mentioned had been rattling cut out all together today..The reason i add urgency to my querry is i see an IHKA on Ebay from a low mileage '95 530 the seller says works perfectly but I am not sure this is my problem..

1) Blower had been rattling and i was preparing to replace that.

2) Blower response had recently rapidly begun to be sporadic , not coming on again after cutting innition while Blower was on but when I would BANG the area under the glove box where the IHKA is hard enough of in the right spot it would come on BUT the speed seemed to me to be touchy. It would not seem to blow as hard as i recall when switched to Max and the other speeds while slower did not seem to step down in speed just all lower speed settings seem the same though slower than max PLUS the speed when on max had begun surging. Understand? It would rise and fall . I replaced the Resistor last year with a new one from BMW Dealer. I also replaced the Yellow Relay in the Fuse Block with a new one from BMW Dealer The only parts not replaced were the Blower motor ( gonna try a working harvest from bone yard @$80), the console switches and the IHKA..

Since the blower was rattling i am going to replace that asap anyway . If when i install it it does not operate and the seller claims it was when removed from the car, what is most likely at fault? The IHKA on ebay only has a day and a half or so left so if the symptoms read like that's at fault i'll grab it. I have the old resistor which i replaced last year before i discovered the problem then was just the relay and i suppose i should grab another relay just in case but if that is my problem i think that would indicate a deeper issue woul it not? Relays failing within a year normal? Thanks for whatever your vast experience may reveal.