How to Change a Stop Lamp Switch

A do-it-yourself auto mechanic must not only be mechanically inclined, but he must possess a degree of electrical aptitude as well. An ignition and brake lamp circuit commonly need of a tweak or adjustment and often prove to be overwhelming to a mechanic unfamiliar with either system. Of the two systems, the stop lamp switch is probably the component most likely to require an adjustment or replacement every few years.

Instructions

Disconnect the negative (black) battery terminal using either a 5/16 wrench or socket head wrench, depending on the type of battery terminal used.

Locate the stop lamp switch. The stop lamp switch will be located close to the pivot point of the brake pedal arm. A 5/16 nut and jam nut secure the stop lamp switch firmly in the switch holder.

Depress the brake pedal by hand to ensure the appropriate switch has been located. If the depressed brake pedal releases the button on the stop lamp switch, the correct switch has been identified.

Disconnect the two-wire electrical plug connected to the back of the switch and move aside.

Remove the 5/16 inch nut securing the stop lamp switch to its bracket using a 3/8 inch wrench.

Slide the stop lamp switch out of its bracket. Take note of the position of the second nut located on the switch before removing it. It is the approximate position the nut will be placed on the new switch.

Install the nut just removed from the old switch on the new switch by hand to approximately the same position as on the old switch.

Insert the new stop lamp switch into the switch bracket. Install the first 5/16 nut onto the switch to secure it in place while holding switch in place with one hand. Use the 3/8 inch wrench to tighten the nut in place.

Connect the two-wire electrical plug onto the new stop lamp switch. The connector will plug into the switch in only one direction.

Depress the brake by hand and observe the switch operation as the brake is released from the switch plunger.

Reconnect the negative battery terminal to the battery using either a 5/16 inch wrench or socket head wrench depending on the type of battery terminal.

Turn ignition key on and function test the brake to ensure brake lights are operable.