I have a 99 ranger an the a.c. fan speed switch isn't working besides the last speed. The first 3 speed dont work. Any idea what it is. A.c. blows ice cold etc. Started lastnight the issues.

 

Welcome to the forum

Most common reason for only high speed on blower motor is failed Resistor block on the motor housing, or corroded connectors on the blocks plug in.
Resistor block costs $10-$25 depending on year

Video here: www.youtube.com/watch?v=BQ1j98NVgjk

Other place it can fail, but less common, on the back of the fan switch in the cab panel, remove panel and have a look for melted wires on the switch.