my heaterfan turns off and on. sometimes its fine other times it isnt on...i hit a bump..its fine! ive had problems with a heater core leaking..is that part of the problem? i am replacing it, dont worry..just wondering if the fan has something to do with it. today i got out when it wasnt working and i tapped on the cylinder looking thing (yeah..where the fan is) in the top corner of the car...it came on! i pushed on all the connections i could see. tthen after work it did it again..i tapped it..it went back on...u guys have any clues?

 

There is only two connections. One blade connector which is the hot lead, the other is the ground wire screwed to the case. I dbout the heater core will affect this because the fan is almost 2 feet away. May be a bad ground, or the hot lead is loose on the connector; start there then work your way back to the HVAC control head.
Good luck