1.0 There is a bundle of wires that feed the lights and turn signal in the back. Right where the different wires separate from the bundle check to see if there is a wire that goes to ground. Make sure it is grounded. or 2.) check to see if one of the filaments in the bulb is burned out. it is a dual filament bulb. yes you have to take off the plastic lens, probably using a star driver.
If neither signal light works, the flasher may very likely be the problem. The hazard lights and the signal lights work off different flashers.
The front or rear turn signal flasher bulb may be burned out and needs to be replaced. The turn signal flasher my be defective and should be replaced. The hazzard lights have a flasher unit of their own. These are found up in under the dash in the steering column area.
Signal flasher is located behind the panel left of the ashtray. Panel has to come off and you will see the signal flasher and the four way flasher.
The 1994 Chevrolet S 10 Blazer turn signal flasher switch can be found beneath the drivers side dashboard. The turn signal flasher switch will be above the gas pedal.
I believe it is in your glove compartment there is an access to your flasher.
The turn signal flasher on a 2000 Chevy Blazer is located under the dash. It is just above the gas pedal and slightly to the right.
It can be blown fuse, defective turn signal Flasher Relay, or blown bulbs. In rare instances it can be a defective turn signal switch.
you need to change the flasher can for the signal lights
I am assuming you have replaced any defective bulb. If none of the turn signals work, replace the turn signal flasher relay.
Buy a "highway" turn signal flasher
Look for either a blown fuse or replace flasher unit for the signal lights (it is separate from the hazard lights flasher unit).