Brake Light Switch - Warning!

[John Naylor]

On a recent club run, a friend commented that either my brake light switch was faulty or I didn't brake much. I often check that they are working when reversing into the garage, checked again that they worked and attributed it to my smooth driving (I have a phone app that measures my driving style and my insurers give me up to £15 a quarter refund on my modern car). Over the last couple of weeks I checked them again as I have had incidents of cars nearly running into me. Only now have I realised that the pressure applied before the switch activates has increased so that only emergency braking activates them. The switch has lasted only 4,000 miles and just over a year and so I have ordered another. I have seen lots of complaints about poor quality switches and thought they either worked or not but suggest we should all be wary and check that they operate under light pressure - the consequences of taking an impact in the rear in our cars without head restraints could be horrific!

[RobThomas]

It has been discussed on here a few times. Overloading the switch seems to be part of the problem. I've just changed to LED bulbs which drop the switch loading by about 80%. The other option is a better switch on the pedal assembly, or even both methods.
Cheap chinese LEDs are cheap for a reason, though.

PS. Only ever use LEDs in pairs due to weird wiggly amp problems causing bulb failures.

[amgrave]

This was a point raised latterly in an edition of Minor Matters, the light not coming on with light pressure on the brake pedal. When I get the chance I am going to have a look at making a bracket up of some sort to put a switch in a position to be operated by the brake pedal. I am not with the car most of the time but from what I remember of the layout it will not be straight forward to do but I used to own a motorcycle that had a brake switch connected to the pedal via a spring and this has given me an idea. If it comes to anything I will take pics and post them for others to see.

[liammonty]

Unfortunately this has been a problem for some time now, and I resorted recently to sourcing a second-hand one as a replacement, instead of buying a poor-quality new one as I got sick of replacing them every year. It's always worth checking the brake lights are working, and as you mention, this is easy to do (in the dark) when you're by yourself by looking for the reflection of the brake lights when you reverse up to something.

There are several items that are just not possible to source good quality alternatives of, like these switches and heater taps etc. I've felt for a long time that it is a big shame that the club doesn't invest some of its assets in order to produce a batch of some of these items (at least safety-critical ones).

[dalebrignall]

that would be a good way for the club to help its members

[RobThomas]

One big killer of such ideas is the product liability issue for the club if they produced brake parts. I'm just going through that at the moment with these negative camber eyebolts.

On my Lenham Healey there was a hole in the high-level brake light so you could see the light when it came on. Very simple to add a tiny bulb somewhere if you were worried about it. I was also looking at adapting the early Minor bootlid badge to take a bulb behind the lens to turn it into another brake light unit. I also secured a source of new reflectors for the badge.

[Mark Wilson]

Fingolfin came up with one approach to the fitting of an electrical switch to the pedal in this long, but good, thread (near the end of the marathon May 24 entry)

http://www.mmoc.org.uk/viewtopic.php?f= ... ht#p584150

[amgrave]

I noted Fingolfin's answer to the problem with his switch but it puts a bit too much sideways pressure on it to guarantee it's longevity and I think it's under the floor open to the elements.

[neilmorey]

Someone in a Herald was following me on a run a few weeks ago, it wasn't until I braked very hard to make a junction that he was definite that the brake lights weren't working and I wasn't just sparing with them. I have halogen rear bulbs so possibly the switch contacts becoming burnt due to the current was the reason for failure?
http://www.norbsa02.freeuk.com/goffybulbs.htm

Searching around it seems that Bosch make a better quality switch, this one from FAE came up as an equivalent, with luck it will be reliable and £4.79 inc. p&p isn't much money.

http://www.eurocarparts.com/ecp/c/Austi ... d3c&000415

[RobThomas]

35 watts each for those tail lights so that will kill the standard Lucas ones even quicker. The downside of LEDs is they are only really good at firing light in one direction and the 'helmet' lights on our Series MM cars point slightly upwards. Lining the bulb holder with Solas tape helps.

[neilmorey]

There is a wiring diagram around to introduce a relay so that the brake lights aren't switched directly in order to reduce the load. A relay may be my next step or LEDs. I like the idea of the brighter halogen bulbs when Traveller rear lights are so small but looks like I may be causing problems by keeping them.

http://www.mgexp.com/article/brake-light-relay.html