Stoplight Switch
 

If your FD is in your garage and its stoplights are on but very dim,
1. Your battery is down to about 9 Volts.
2. Your stoplight switch (P/N BR70-66-490A) is broken (see the plastic pieces on your floor mat?).
3. You will need to make a special order; price will be $80.42 from your dealer.
4. Part will come from warehouse, if it's there.
5. You will wonder how far down the road you will be when your clutch switch goes out.
6. You will wonder why you are still the car's original owner after 31 years.

Are you sure? The acorn pieces are not the switch itself

It is usually not the switch itself, but the little plastic stopper on the pedal assembly. Most cars have this issue over time. If your battery is run down its probably because the lights were on for a long time. It is possible for the switch to fail internally and complete the circuit but I've never personally seen it. They typically fail open so you don't have any brake lights, i've never seen one fail closed. If you have plastic on your floor, 99.9% chance its the stopper.

It’s not the brake switch it’s the plastic/rubber stopper… which caused the brake lights to stay on and drain the battery.
Replace the stopper and charge the battery then you’ll be good. 👍
I’m speaking from experience.


Steve

Well, that's embarrassing! Thanks to all for your help... I just wish I hadn't already ordered the switch. Maybe after Labor Day I can cancel the order. I didn't see in the 1994 Mazda parts list any reference to that "button." Is there a Mazda part number, or should I go to Nissan and order a bag of those from them?

Edit: Never mind. Amazon has the equivalent:

Edit #2: I confirmed that the 1994 FD parts catalog does not show the "button" for either the brake or clutch pedal (manual transmission), or either for the brake pedal on the auto trans page. If it had shown a part, I probably would have figured that out.

The part i used in that video is actually a Nissan Part number. Local dealerships may stock it

Received a package of 4 of those plastic buttons from Amazon today and tried putting one in. Can't do it. The brake pedal can't be pressed far enough to allow the plastic button to be aligned properly to be pushed through the brake pedal lever. Tried for a long time... have a bloody arm to prove it. Wife will take the FD to Neptune Speed along with the spare parts. Hopefully Yoshiya will be able to work his magic. Too bad the video, which was otherwise excellent, didn't show HOW to install it without blood. 20 - 30 seconds??? Not on my FD!

turn the car on so the brake booster works and the pedal will move much further than with the car off

This right here. If you pump the pedal a bunch without the car running and no vacuum applied to the booster, the pedal with eventually become rock hard with barely any travel if you didn't get the plastic part in within the first 3 or 4 pumps. When you start the engine, vacuum will be applied to the booster and the pedal will go WAY down giving you plenty of room to slip the stopper in.

Okay, I will try that, thanks much for the tip! Will have to connect the battery again, of course... to start the engine. Don't know if my thumb is strong enough to push that thing in, though. I'll try it.

Edit: Hey, it worked! Starting the engine allowed the pedal to be pushed down enough to put the new button in. You folks saved me a lot of trouble! Thanks much... I learned something, too.