Swap the motor from an H22A1 to an H22A4

I'll replace the driver's side, then a couple months later, the passenger side, then 6 months later, the driver's side again. It's never ending. I've had the car for 12 years and it seems lately the problem is getting worse. I only drive this car about 3000 miles per year, so it can't be over-use. I've used different brands of lights. No difference. Has anyone else had this problem or know why it's happening? Thank you.

Does anybody else have problems with the air in their lude? My ac does not work in the first place but that doesn't bother me as much as the fact that just vent air is heated more than outside air. And now it's winter. On cold nights the car has a hard time keeping the cab warm enough for comfort. The engine heats up great so I know it is not the thermostat. I would am wondering if this a common problem. I'm thinking of changing the heater core.