1990 Ford Bronco BRAKE LIGHT SWITCH

Lift the locking tab on the switch connector and disconnect the wiring.
Remove the hairpin retainer, slide the stop lamp switch, pushrod and nylon washer off of the pedal. Remove the washer, then the switch by sliding it up or down.

On trucks equipped with speed control (cruise control) , the spacer washer is replaced by the dump valve adapter washer.

To install the switch, position it so that the U-shaped side is nearest the pedal and directly over/under the pin.
Slide the switch up or down, trapping the master cylinder pushrod and bushing between the switch side plates.
Push the switch and pushrod assembly firmly towards the brake pedal arm. Assemble the outside white plastic washer to the pin and install the hairpin retainer.

CAUTION
Don't substitute any other type of retainer. Use only the Ford specified hairpin retainer.

Assemble the connector on the switch.
Check stop lamp operation.

CAUTION
Make sure that the stop lamp switch wiring has sufficient travel during a full pedal stroke!

May have bad wiring to that taillight, it may have a short in it which could be why the previous owner decided to remove the brake switch instead of fix the issue.