1986 Ranger 4 cyl. 2.3 Liter gasoline 2WD. Power Brakes. Customized interior cab lights.
Replaced power brake booster and master cylinder. Brakes now work fine, but can't get either new Borg-Warner switch or old brake light switch to operate when installed on pedal. Old switch works fine when operated by hand (removed completely from brake pedal) in a circuit that starts with a hot wire direct from battery through 15 amp fuse to old brake light switch.

Bulbs at rear of truck that were lit up were the two-filament 1157 bulbs that are for tailights and turn signals.
1156 single filament bulb at bottom of left rear lens housing was unlit.

In this case, output from switch went to black wire which was routed from vinyl sleeve which had descended from wiring harnesses and joined green wire with red stripe.
For the manual test, black wire was seperated from green w/ red stripe wire.

According to the Haynes Ranger manual, Green w/ red is the proper output wire.

Neither old or new Borg-Warner switch works on pedal in any wiring configuration.

Switch is non-adjustable, both from observation and Haynes manual description.

Also, custom install cabin lights are knocked.

Very mysterious.

Keeping me from a job I could go do right now!

PS: On-pedal testing was done with both original hot feed wire and fused hot lead direct from battery.

 

it appears that there is nothing in original design that holds the brake light switch stationary against the brake pedal, SO that when the pedal is depressed, the power booster plunger rocks against the cam at the front of the switch, causing the cam to move and the circuit to engage. In a shop test, Tim, owner of Select Electrics in Berkeley CA, removed the nylon bushing and the outer spacer, and now the brake lights work. Obviously, we don't want to leave it like that.
Perhaps the aftermarket booster has a round eyelet in the plunger, while OEM may have had an elliptical hole. Any comments or suggestions?
Thank you in advance for all your help.