GM-GMC: no start, brake light switch, chevy 454

Question
I just bought a 1994 chevy 454 one ton dually 4x4 manual transm (hydralic clutch) truck to pull my horse trailer.  when I put the clutch in to start the engine nothing happens (headlights stay bright if I turn them on).  the accessories/ lights all work and battery is good.  it seems like the safety on the clutch pedal is not disengaging to allow the engine to turn over. Can you tell me where that safty switch is?  any other ideas of what the problem might be?

Answer
The switch should be near the top of the brake pedal arm and may be a part of the brake light switch.

The other possibility is a bad ignition switch.  It is located on top of the steering column down near where the column goes through the firewall.  The steering column has to be unbolted and dropped down to get to it.

I recommend that you go to an auto parts store and buy the clutch safety switch (or brake light switch if the start safety function is part of it).  This will show you what it looks like and you should be able to find it on a bracket near the top of the brake pedal arm.  Change the switch and see if you can start the vehicle.  Note that the switch may need to be adjusted to keep the brake lights from coming on without stepping on the pedal (or to make them come on when the pedal is pressed).