Many of us have replaced the radios in our Fieros with late 90's or early 00's Pontiac (Delco) radios. Sometimes the volume controls on these radios go "crazy". The volume goes up when you try to turn it down, or vice versa, and it can be very annoying.
I figured out a very easy fix for this, which is presented below.
First, carefully remove the face plate of the radio. The face plate actually has the control part of the radio attached to it. Use a flat screw driver blade to pry up the tabs that hold it in place.
Turn the radio bottom side up, and pull the control assembly out a few inches from the rest of the radio. It is attached to the rest of the radio with a flat cable, but there is no need to disconnect it.
The volume knob is removed from the radio in the above picture. You can see the control assembly that the shaft goes to. The volume control is not a conventional potentiometer, but a sequencer switch.
Spray the switch with WD-40 at the place where the black plastic part of it meets the metal part, as in this picture. But don't hold the WD-40 straw at an angle like the picture. Hold it straight up and down.
This close-up shows the place to spray. After you spray, wipe off the excess with a tissue or paper towel. Try turning the volume knob.
The clicks it makes as you turn it should be louder than before you sprayed. If they are, the control is fixed. Re-assemble the radio, and put it back in your car. Enjoy a normal volume control.
