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

[sugarwood]

My brake lights don't go on unless I use excessive pedal pressure.
I only realized this because someone informed me at an intersection.
This might be a good thing to verify on your car as it may not be flagged at your annual inspection.

If you replace the 2 brake light switches,
make sure you order the right 2 or 3 prong switch.

I began this repair today.
First remove the carpet, cover plate, cross bar, and detach 2 air hoses to access the 2 switches.

Unfortunately, both of my switches have clearance issues.
The front switch has a brake line that crosses right in front of it.
I found an image online that does not look like my brake line routing.
I suspect my brake line may have been replaced at some point, and not routed correctly around the switch.
There is no way to get an 22mm offset wrench or 22mm socket onto the switch.
Can't get an opened ended wrench in there either.

Will probably take it to the shop and report back how they approach it.
Maybe they'll need to detach that brake line.
I wonder how much play, if any, that would create.
The other end is attached to a rubber hose, that can be detached from the bracket, resulting in possible play.

I will post an update when I get this resolved,
In the meantime, I advise others to do a quick check of their brake lights!

[manbridge 74]

Done a lot of these over the years on both 911 and 930. While clearance is tight I don’t recall any major disassembly to replace.

[david.avrahami@]

2 switches from my 87 Carrera are for sale today...reason? I changed them with new ones but found out afterwords that a burnt fuse was the problem....
See my 87 Carrera for sale listing.

[GH85Carrera]

One of the checks I do every so often is hit the brake pedal while in the garage to see just how hard the brake pedal has to be pressed for the lights to come on. It is scary to be out and about while driving and realize the brake light only come on in hard stops.

I have a offset box end wrench to R&R the switches. I bought it just for that purpose.



I just bought the one, and not an entire set, but a wrench like this is great to get the switches off and on.

[garment]

sub'd - I have replacement switches on my workbench now...

[darrin]

Originally Posted by david.avrahami@

2 switches from my 87 Carrera are for sale today...reason? I changed them with new ones but found out afterwords that a burnt fuse was the problem....
See my 87 Carrera for sale listing.

David -- this happened to me years ago, traced the blown fuse to a failing cruise control module -- hit cruise control level (even accidentally) and brake light fuse would blow - FWIW

[manbridge 74]

Flex head ratchet wrench works well.

[thsupernge]

This is great guys, thanks for posting!
I literally just discussed this project this morning! This is a critical safety issue and needs to be addressed. My brake lights only come on if I am standing on the pedal-NOT GOOD!
I used to do these all day on bugs and the like but the access is not easy on the 911.

Are you tefloning the threads...etc.?

Any help, tips, tools, advice-pics etc are HUGELY appreciated!
You guys are awesome!

[manbridge 74]

Teflon is for house plumbing, no need here.

[sugarwood]

Originally Posted by thsupernge

Any help, tips, tools, advice-pics etc are HUGELY appreciated!

The best tool appears to be a deep offset wrench 22mm.

Before your order, verify if you have 2 or 3 prong switch.

My case is unique because the brakes lines have benn replaced and not bent correctly. I will need to detach and move the brake lines, and then bleed the lines.

[thsupernge]

Cool, I was thinking maybe a crow's foot might be able to get in there too. Any recommendations on sensors (2 prong)? I have been told just to buy the german made units or the corresponding vw models because they last much longer.

[sugarwood]

Crowfoot
7/8" is 22mm

I got the ATE brand since I read that cheapo brands may leak.
Since the R&R is a hassle, I'd rather only do it once.

[Satanas]

Or you can install an electric switch.
This way, your brake lights come on as soon as you stroke the brake pedal
(Use google translate)

https://pcxsubxci2xux76xb2ippjepji-adwhj77lcyoafdy-www-type911-org.translate.goog/blog/?idblog=10919

[thsupernge]

Originally Posted by Satanas

Or you can install an electric switch.
This way, your brake lights come on as soon as you stroke the brake pedal
(Use google translate)

https://pcxsubxci2xux76xb2ippjepji-adwhj77lcyoafdy-www-type911-org.translate.goog/blog/?idblog=10919

Oui je vois. Merci beaucoup! Était-ce difficile?

[Marc Bixen]

Basic rule of thumb, and there may be a couple of exceptions, 3-wire >83, SC, 84>3.2's are 2-wire.

[sugarwood]

Originally Posted by Marc Bixen

Basic rule of thumb, and there may be a couple of exceptions, 3-wire >83, SC, 84>3.2's are 2-wire.

There is overlap
3 prong. 1977-1986.
2 prong. 1984-1989.

[911obgyn]

Mechanical switch for me

[emac]

Originally Posted by 911obgyn

Mechanical switch for me

I did the mechanical switch works great but I have this issue. 81sc with three prong switches. As soon as I press the brake pedal I get Instant brake lights but my parking brake light turns on and will not go off.
Suggestions—ideas?
Ernie

[Satanas]

Originally Posted by thsupernge

Oui je vois. Merci beaucoup! Était-ce difficile?

Not difficult, see electrical connection:

https://pcxsubxci2xux76xb2ippjepji-adwhj77lcyoafdy-www-type911-org.translate.goog/blog/?idblog=10915

[dan88911]

+1 more, I add something like this to my brake lights a few yrs. ago
Mechanical Brake Light Switch Modification - '78 SC