The following modification illustrates how to mount a clutch pedal activated electrical switch. The switch could be used for various functions, from providing power to a device when the clutch pedal is raised such as activating 2 steps, line lock, data recorders, or it could be used to remove power from a device. For example it could prevent the starter from turning when the clutch pedal is not being depressed.
As usual, my example is for a 65/66’ Mustang but the procedure should also apply to several other cars with similar type pedal assemblies.
First I procured a common switch made by Micro Switch:
The Microswitch show above (bz-2rw80-a2) is readily available from various sources such as Allied Electronics for about $10:
Honeywell / Microswitch - BZ-2RW80-A2 - Allied Electronics
These are small, but heavy duty industrial switches that have a long lifespan. The switch shown offers both a normally open and a normally closed set of contacts. How it is wired is up to you. You will also need to find 2 small diameter bolts/screws that will pass through the holes in the Micro Switch plus some nuts that fit the bolts for attachment purposes. For my example, I used 6-32 1” long hex head bolts.
Next locate a 2 x 4” piece of metal, approximately 1/8” thick. For my example I used a .090 thick piece of aluminum (although I have also used .060 thick aluminum with success.) For this tech article I will call this the switch bracket.
The switch bracket will be attached to the clutch pedal stop bracket. The clutch pedal stop bracket is easily removed from the clutch/brake pedal support with a wrench. You will see this factory stop bracket on several of the following photos, but not by itself.
Take the piece of aluminum and fit it to the top of the clutch pedal stop bracket, opposite where the rubber pad is mounted. It will require a little notching to fit nicely. Then take two 3/8” self-tapping screws and attach the metal to the support. The short screws will not pass all the way through the rubber stop. Look on the right of the following pic and you will see the heads of these attaching screws.
Next temporarily mount the new assembly back on the clutch pedal support. I suggest using a normal nut instead of the factory locknut as you may need to test fit your parts several times. This is a temporary holding device so that you can determine where the switch needs to be located on the switch bracket. Position the switch on the underside of the switch bracket and make sure that the switch can contact the clutch pedal when the pedal is in the upward position. Then mark where the switch appears to mount the best and the switch paddle can touch the clutch pedal.
Once adequately marked, remove the clutch stop bracket from the clutch/brake pedal support. Next measure the distance between the mounting holes of the Micro switch. You will want to use this measurement to mark the switch bracket where the switch was positioned before. Once satisfied that the switch will mount in the predetermined position, drill holes for mounting. Because I wanted a highly adjustable switch, I drilled multiple holes in a straight line and ground them into a slot with a cutoff tool:
I then mounted the switch to the switch bracket using the 6-32 screws with the nuts being located on the upper side of the switch bracket.
The assembly is now ready to be mounted permanently to the clutch/brake support bracket under the dash using the factory bolt and locknut. Once the assembly is installed, the action of the switch can be tuned by either loosening the bolts and moving the switch along the slots or by bending the paddle that is part of the switch.
In conclusion, I have found that this switch is very useful for me at the dragstrip and it has helped improve my consistency off the line. I have mine wired to the 2 step module, the line lock, and the data acquisition tach. At launch the clutch pedal hits the switch paddle at a predetermined pedal height. The switch then turns the 2 step and line lock devices off plus it also starts the tach’s recording mode.