My fan will come on for 20 seconds ramdomly now and then 10 minutes later the car will over heat on the dash and the fan wouldnt of kicked in what is the problem? Soon as i put the heaters on temp comes down to normal level hot air coming through and will be fine soon as i turn the heaters off over heating again and fan wouldnt of kicked in? I have checked fuses and changed fan switch still the same ? Any one help? Maybe temp switch not working correctly?