My first post so bare with me. I replaced the heater core in my 97 F150 last week and all went pretty smooth considering it was my first attempt at such a feat. Problem now is that my air bag indicator flashes a code 52 and after a few miles my check engine light came on and stays on. I've never had any serious problem with the truck and it has been maintained very well for its 158000 mile lifespan. I've checked and rechecked and rechecked again to see if I may have missed a connection somewhere all to no avail. Anyone have any idea what I missed?

97 F150 XLT
4.6L