Had the same problem on my 1990 s-10 blazer, after pulling the door skin,i found the linkage to inside door handle had bent, just bend it out straighter is all it takes.
Need to know inside or outside door handle.
Check inside the vehicle in the passenger side kick panel or behind the glove compartment.
behind the passenger side front inside wall panel next to glove box
Passenger side bottom of engine.
Behind the passenger side of the dash.
Bottom of the motor, passenger side.
Under the hood, passenger side, firewall, close to passenger fender.
fuel pump is located on the inside of the chassis rail on the passenger side about level with the rear of the front door
The oil cap on a 1998 Chevy Blazer is located on the passenger side of the motor. It is just to the left of the manifold cover.
Inside the voltage regulator on the alternator.
The tire jack is located in the rear inside of your Chevy blazer. The jack can be found in a side compartment.
Set fire to it!