I ordered a replacement mirror (glass only) for the existing one fell out. I received it and it has a plastic back with two electrical polls for the heater.

My question is how do I remove the old backing and pop in the replacement. It looks like it has plastic pop pins, should I just pop the old plate out or is there a trick to it.

When I am driving, all the dashboard lights come on and the car loses all power. I pull over and it starts right back up. Sometimes it does this two or three times a day and sometimes not at all. Any ideas? My mechanic can't figure out what is wrong. Everytime he drives it, it runs fine (of course).

My airconditioning system does not work effectively. It is fully gassed up, but the compressor seems to be cutting in and out, I suspect it is my outside sensor. The inside of the car gets too hot before the aircon starts to work but not for long. and the compressor cuts out. Is it the sensor. I believe it is behind the glove compartment. How do I
get there and what do I do to fix it.

how much to replace heater core ?parts and labor?

I inherited the car, no idea about prior maintenance. Sometimes starts right up, but often after being driven takes 10 -20 minutes before starts. I also do not have an owners manual.