PSA: Check your brake lights. (and then get stuck trying to replace the switches)

[sugarwood]

Originally Posted by 911pcars

There’s a large variety of mechanical switches, all adjustable depending on actuation distance. Install in any convenient location in the pedal actuation system. The brake pedal and link to the MC are often used locations.
https://www.amazon.com/universal-brake-light-switch/s?k=universal+brake+light+switch&page=2&qid=1616524224&ref=sr_pg_2
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Once you mount the aftermarket switch at the pedal,
you snake the wire and feed it into the original switch connector at the M/C ?
So, you'd also need additional spade adapters and longer wires.

Interesting alternative, but I am not a fan of aftermarket wires running throughout the car.
Makes things confusing for the next owner.

[walt]

Forget the pedal, easiest way is to mount the mechanical switch on the master cylinder. Tons of information here on various mounting methods.

[thsupernge]

Originally Posted by sugarwood

That blade is wider than the gap between the prongs.
Since you had to saw diagonally, I am guessing you were not able to cut it flush?
No seatment issues ?

It fits and I filed the rest.
Nope...

[L Sjoberg]

swapping out the brake light switches is a job that I still have nightmares about, almost 4 years later. the original switches made it almost 25 years, hopefully the replacements make it that long.

[GH85Carrera]

The factory put in two switches for redundancy. The fact that the both get old at the same rate just means you need to likely replace them every 25 to 30 years as maintenance. It is not that hard to do, and sure beats some home made bodge. The factory moved away from the pedal mounted switch for a reason. On my 914 I had to replace that switch twice because of getting in the car with wet feet and the pedal area is a dirty area.

If an old fat man like me can replace them fairly easily, anyone can. It is your car, do to it what you want, but check your brake light function regularly regardless what system you go with.

[thsupernge]

Originally Posted by GH85Carrera

If an old fat man like me can replace them fairly easily, anyone can. It is your car, do to it what you want, but check your brake light function regularly regardless what system you go with.

Hard to disagree with?

[sugarwood]

Ordered a cheap switch for $8.
It matched the part better than the ATE brand
Correctly sized 22mm, so I got it installed easily.
Verified the brake lights now work again with a light touch.
I now have one brake light switch, and the car is back on the road.

[thsupernge]

Touchdown!

[911pcars]

Originally Posted by sugarwood

Ordered a cheap switch for $8.
It matched the part better than the ATE brand
Correctly sized 22mm, so I got it installed easily.
Verified the brake lights now work again with a light touch.
I now have one brake light switch, and the car is back on the road.

Air bubbles stayed away?

[sugarwood]

A little bit of fluid dropped out onto the catch rag.
Brakes light up with barely any pressure.
Brakes work fine, but I'll flush the fluid in the Spring.

[thsupernge]

Originally Posted by sugarwood

A little bit of fluid dropped out onto the catch rag.
Brakes light up with barely any pressure.
Brakes work fine, but I'll flush the fluid in the Spring.

That's good, mine drained out, I lost half a 'tank.'

[MikeDL]

I went through this (twice!) with my '84. The second time, I took apart the switches and found the contacts quite damaged due to arcing. When I put the second set of switches on, I added a relay to protect them. There are several threads on the problem here, if you're interested.

[911obgyn]

There are 2 switches to carry the amperage of the brake lights from what i understand. The switches are rated at 6amps? I think that one switch will fail sooner than 30 years.

[sugarwood]

Originally Posted by MikeDL

I went through this (twice!) with my '84. The second time, I took apart the switches and found the contacts quite damaged due to arcing. When I put the second set of switches on, I added a relay to protect them. There are several threads on the problem here, if you're interested.

How did you take apart the switch? I'd like to take apart my old one.

[MikeDL]

I used a Dremel around the outer edge of the case to free up the switch guts.

It's a pretty common problem as the cars age

https://forums.pelicanparts.com/porsche-911-technical-forum/422337-anyone-hear-about-solution-failed-brake-light-switches.html#post4087694

[_sponge_]

Following along as this is next on my "to-do" list. I am in the process of trying to make the Cruise Control unit in my 1982 911sc function.

[sugarwood]

Just noticed that my brake lights do not light up anymore.
I need to revisit. Last time in 2021, I only replaced one switch.
Could it have failed already? I barely ever drive the 911 the last few years.
Could the switch be stuck? Can I remove and jam a pick in there?
Could there be an air bubble at the switch?

[sugarwood]

Which fuse is for brake light? I should check that also

[wazzz]

Originally Posted by sugarwood

Which fuse is for brake light? I should check that also

Diagram for 86 Coupe shows this is fuse number 4 (8A) on fuse box I. Should be a green/blue wire.

[sugarwood]

Originally Posted by wazzz

Diagram for 86 Coupe shows this is fuse number 4 (8A) on fuse box I. Should be a green/blue wire.

No, it is fuse #7
https://imgur.com/a/p0rGOjM

My fuse is intact.
I will order a new switch