89 audi CQ help needed

Hey guys! Well I need to finally fix whats wrong with my rad cooling fan. When i shut the car off, the fan comes on like it should.. but when it gets to the overheating temp, it never comes on for some reason. I put in a new temp switch in the radiator, but no luck. I put in 2 other switches and no luck with those. I am not getting any power to the connecter that hooks onto the fan switch, what is my next step? Id like to fix it since there has been a lot of autobahn construction going on, and traffic is getting worse.

I am going to attempt to change the fuel filter. I was told you need to put a wrench or pliars on the old filter housing, and use a wrench to take the fitting out. How tight should the fitting be when I reinstall new filter? I don't have a torque wrench. I don't want to break the lines.

Also, the drivers side seat heater has never really worked. I put in a new switch, which illuminates or does not most of the time.. The other day my seat heater just started working suddenly... now its not working again. Who ever had my car before me cut the wires for the radio that used to be there. I taped up all the wires thinking they were causing a short. So far, the drivers seat heater switch lights up every once in awhile, and seat heater isn't working. Can anyone help me out with that?


Thanks in advance!