air bag light blinking

[yellow95stang]

first off I have a 95 mustang and i need some help.

yesterday moring my coolant light came on for my 10 mile ride to work. Then at 12:00 when I went to lunch the light was off.
Later on at about 6:00 pm I swapped out the head unit for a diffrent one. However I liked my old unit better and put it back in.

Then when I went to drive the car this moring and the air bag light was blinking. it seemed to be blinking a 12 code for about 4-5 repitions then it would stay on.

After I finishend my classes I went to the store to buy a code scanner and when I was leaving I let the car warm up. After about 2 min. It started to drop about 3oo rpm every 10 seconds. I popped the hood and and the ac compressor was freezing up every 10 seconds, which was making the car idle funny. I turne d the car off and drove it home and it was fine, except the air bag light was on.
Next, i ran the koer code and it seems to be in working order. I wasn't really sure about the koeo code but I am going to run it again.
I also tried erasing the code but it didn't work. I left the battery disconnected for about 1 hour, but that didn;'t work either. I pulled the cd player and everything looks ok. The antifreeze was good but i topped it off anyway. Nothing seems to be working. I am new to efi mustangs but have had many carbed stangs so I am not really up on the computer controlled engines, sooo... any and all help would be much appriciated. THANKS - Rob

I just ran the engine codes and everything is ok. however the air bag light is still on.