My annunciator # 1 light is on and I think the brakes are bled properly. Does anyone know if I can remove the contact housing(see #3, Fig. G14-1, TSD G14-1) to this this switch to test, and how do I test it?
The lamp should go off when the motor is running and pressure is built up to prevent the switch from grounding, causing the circuit to complete to ground.
You can get a false positive but it would be more important to find out if the lamp comes on due to low pressure in the system. The switches can be bled to elimate air at the switch piping.
Given how easy and inexpensive it is to build a pressure gauge to test these systems, I suggest that any DIY mechanic do just that. That way you get a definitive answer, or as close as you're going to get to definitive.
Bleed the switches first.
If you still have a problem, remove switches and open them then replace diaphragm and check the main pin pushed by the diaphragm.
Pin should be replaced if old and smashed and stuck. Pin should be free and moving with diaphragm movement from pressure...