I have a 1986 chevy celebrity check engine light comes on how do I check codes?

You have to use an OBD-1 scanner, they are still available. There is a port under the dash, or you could use something to bridge pins A and B, turn the key to where everything turns on, but don't start it, and it'll flash the code using your check engine light. Example-blink(pause) blink, blink=12. They have a whole list of codes for that if you search it. I just did that on my 1985 Celebrity Eurosport.

I'm sorry to say but cars under 1995 can not be code read.