85' 911 wont start? Blower relay??

[Blusi19]

Ok I have a 85' 911 that will not start. It cranks and cranks but just doesnt start. I had this problem a few months back and did some poking around and disconected the blower relay, which is the one on the driver side engine compartment, silver looking relay behind the black cover in the side. Well I disconnected it and looked at it, reconnected it and the car started up. Now the car is doing the same thing and I can not get it to start. I need to know what does this blower relay control?? I found out that this relay is like 180 dollars, so I need to know if this is my problem and what it controls? Also I was checking the coil to see if it was getting power and when the ignition is on the coil gets power on the postive side, but not on the negative. Is this normal?? Any help is appriciated.