[pjmoreland]

You can use the resistance setting on your multimeter to check continuity. You touch one probe on one end of a wire, and the other probe on the other end of the wire. A low reading means you have a connection, similar to the reading you'd get if you touched the two probes of the multimeter together. You can use this technique to determine if you have a good connection between the ground side of the brake warn light and the two tan wires on the ignition switch. Testing in the resistance mode should be done with the truck electrical system turned off.

Instead, though, you could use the same technique you used with a grounded wire to test the connection from the ignition switch to the light. If you short the two tan wires on the ignition switch to ground and the warn light turns on, then the connection is good. This approach is a little more risky than using the multimeter because you could accidentally damage something if you connect ground to the wrong spot.

Either way, the goal is to verify you have a good connection between the ground side of the brake warn light and the ignition switch at the two tan wires. This connection also includes where one of those tan wires connects to the back of the gauge cluster, so there could be an issue at that connector as well. Watch out because there are two separate tan wires on the gauge cluster connector. You want the one that is NOT next to the empty terminal slot on the connector (that one is for the fuel gauge).