Faulty brake lights

JIMMY911SC · 06-10-2012, 03:32 AM

Hello, can anyone help found brake lights not working checked no power then found out no horn and heater fan do they get power through a relay or from the igintion switch .I have got a diagram and can see T6/6F in circuit but don't know what it is?

thanks jimmy

steely · 10:55 AM

Hi Jimmy and Welcome to the madness.

I only have a book for the 84-89, you say you have an SC, is that '82? For example, my horn is on a relay and the brake light fuse is different than the horn. Let us know the year for better results.

The "T" is shorthand for connector, and the 6's mean connector nbr 6 and there are 6 wires in it - you are looking at the 6th or "F"th wire - I may be mistaken. Correction(?), I think the letters are the location of the wire according to the 78 SC schematic legend found using the link on our hosts main page. http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_78SC_USA.pdf

According to the 82 schematic, the horn and brake lights share this connector. I would check this out as it sounds suspicious.
If the rear side markers are working, your grounds are good (for the ones shared with brake lights), but I didn't check power or return paths too deeply.

Where did you say you had no power, at the light with the brake depressed?

Post a pic of your car sometime (its a tradition thing - nothing to do with the power problem).

JIMMY911SC · 06-11-2012, 09:22 AM

Hello Dan,my car is a 1980 .I have no power to the brake light switches and fuses for the heater or horn. I have also found on the drawing that T is a connector but i don't know where it is on the car to check power from the ignition, all points to the switch but will check out more before getting one

thanks for your help jimmy

this is my car

Quicksilver · 06-11-2012, 10:28 AM

The most common failure (besides burnt out bulbs) is the brake light switches on the side of the master cylinder. They are pressure switches wired in parallel and they can get so they need higher pressure to turn on or they just plain fail. Try jumping across the 2 connectors of the socket and if the lights come on you know the switches are bad.

JIMMY911SC · 06-21-2012, 09:17 AM

Happy NOW found bad connection on joint on supply to fuses, so got heater working then found horn faulty so replaced then found brake light switches both faulty rewired put new switch in footwell and she passed MOT NO PROBLEM, HAPPY DAYS

Uneekone · 07-15-2012, 06:20 PM

Can someone post a picture of these switches? I am having a similar issue with my 83 Targa. The horn and all of the lights work except for the brake lights and the back-up lights...

BobbieShen · 06:32 PM

They are pressure switches wired in parallel and they can get so they need higher pressure to turn on or they just plain fail.

Uneekone · 07-15-2012, 06:47 PM

Bobbie-
Why are you reposting Quicksilvers post? I was able to read that just fine but that still doesn't help me locate them on the vehicle. Maybe its obvious and I just totally missed them when I was under there earlier tonight looking around. Maybe its not...

timmy2 · timmy2's Garage

Pics here:
No brake lights which switch - PICS
Everything you needed to know about them and more here:
Pelican Parts Technical BBS - Search Results

JIMMY911SC · 07-16-2012, 12:23 PM

Hello, my brake light switches are 2pole so n/o and n/c so three connections at switch ,after reading about the common faults on these switches i fitted a new switch on the board at the brake pedal with 2x 3.5mm nuts and bolts and took a 3core flex back to the old switches and just extended the wires with push in spades. all worked prefect nice neat job on wires on show.
I used a switch from RS Components no 664-727 it is a 250v 15amp ip54 mircoswitch but when you read the spec it's rated at 12v 8amp it's about £20 but i thought it did the job best for me but you should look around and see whats is best for you.If you need pics will take carpet up no problem to show finished job
hope this helped
jimmy

spuggy · 07-16-2012, 04:43 PM

Quote:

Originally Posted by Uneekone

Bobbie-
Why are you reposting Quicksilvers post? I was able to read that just fine but that still doesn't help me locate them on the vehicle. Maybe its obvious and I just totally missed them when I was under there earlier tonight looking around. Maybe its not...

Because "BobbieShen" has nothing of interest to contribute to this thread, likely to this board. Probably doesn't speak English, so quotes someone else on the thread. In 6 posts, this user has yet to write word/phrase one that wasn't previously posted by someone else in the same thread.

If you do a search for posts by this user, you can see the spam payload in the original post - which he has apparently gone back and edited out in 5 of the 6 posts (and probably forgot to enter in the first place on the 6th).

Reported to the tireless and ever-vigilant Mods.

Back on-topic; I don't know why so many guys have issues with the brake light switches; mine work fine. Maybe you don't drive the car enough?

Uneekone · 04:26 PM

timmy2-
Awesome! Thank you!

spuggy-
I drive it as much as I can! Who knows how long the brake lights have been out though! The sensors are ordered and on their way. Hopefully that addresses the problem...