I just bought a 1988 190E. I have noticed something strange. Every other time I would start the car, the fan(blower motor) for the A/C or heat would not work. You could turn the fan on high and nothing. Then I noticed one time I had the fan on and it was not working and I brushed against the keys in the ignition and the fan came on. Now every time the fan does not work, I just turn the key back just a little and the fan comes on. Can anyone tell me what is going on or what to check. Thanks in advance.

-Chris P.