I have a 97 chevy blazer, that has no headlights. the daytime running lights, dash and marker lights all work but not the headlights or high beams?
It could be many things. How about checking the headlamp relay (assuming your Blazer has one)? Other than that, I would check fuses and the bulbs.
I would add that the headlight switch is also a possibility. They are failure prone. The switch is very inexpensive (about $20) and easy to R&R. You can sometimes check a bad one by snapping them on hard. If the headlights comes on then replace the switch.
There may be a relay that is used to bypass the DRL light resistor and turn on the headlights and there is a faulty connection to it from the switch.
If you plan on keeping the vehicle for some time purchasing a factory service manual would be money well spent so you could have it on hand to refer too for troubles like this.
thanks for the suggestions, it turns out it was jus a bum switch.