I recently bought a 1st gen 1994 s15 Jimmy. The people who owned it before me told me that the fan wont work for the heater unless you hit the top of the dash hard with your hand. Im wondering what the cause of this could be. I tried searching the forums and around online for what the issue could be but I can’t seem to find anything about that specific problem. Im not very experienced with heaters and stuff like that. If anyone can help me out it would be greatly appreciated.