Brake light switch - bypass (?)

Discuss Electrical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
rsawatson
Minor Fan
Posts: 231
Joined: Thu Feb 05, 2009 2:59 pm
Location: West Sussex
MMOC Member: Yes

Brake light switch - bypass (?)

Post by rsawatson »

I wish I had kept the relevant edition of Minor Matters, but a year or so ago there was an excellent article in Technical Tips which detailed a simple way of overcoming the problem of the standard equipment brake light switch from failing prematurely (which newly manufactured ones apparently do). From memory, the solution involved some sort of relay in order that the contacts inside the switch are put under less load (or at least that's what I remember).

If anyone has any advice on this/knows which edition of Minor Matters it was and would be able to take a photo/scan of the article, I'd be very grateful.
Ryan Watson


Mark Wilson
Minor Addict
Posts: 956
Joined: Fri Aug 26, 2011 12:42 pm
Location: West Yorkshire
MMOC Member: Yes

Re: Brake light switch - bypass (?)

Post by Mark Wilson »

I haven't got the article, nor do I remember seeing it, but the principle would presumably be to reduce the current amps at the switch by inserting a relay close to the switch, as follows:
  • Remove the Lucar connector from the lamp side of the brakelight switch and connect it to terminal 87 of a standard Normally Open relay
  • Add a piggy back connector to the battery side of the brakelight switch and connect from this to terminal 30 (thus connecting the battery feed to the lamp via the relay, not the switch)
  • Make a new connection from the lamp side of the switch to terminal 85 of the relay
  • Connect terminal 86 of the relay to earth (thus causing the brakelight switch to activate the relay)
I haven't done this myself, as I have changed all my lamps to LEDs, which achieves the same result of reducing current at the switch.

Hope this makes sense

Mark
KeithL
Minor Fan
Posts: 449
Joined: Mon May 24, 2010 9:06 pm
Location: Worcestershire
MMOC Member: Yes

Re: Brake light switch - bypass (?)

Post by KeithL »

Is this the article you were referring to? It is two parts with an addendum the following issue. The quality may not be very good as I can't upload PDFs and so have had to take screen shots. PM me if you want me to e-mail you the PDF.
Brake Lights #1 Jan-Feb 2019.JPG
Brake Lights #1 Jan-Feb 2019.JPG (449.67 KiB) Viewed 762 times
Brake Lights #2 Mar-Apr 2019.JPG
Brake Lights #2 Mar-Apr 2019.JPG (414.49 KiB) Viewed 762 times

rsawatson
Minor Fan
Posts: 231
Joined: Thu Feb 05, 2009 2:59 pm
Location: West Sussex
MMOC Member: Yes

Re: Brake light switch - bypass (?)

Post by rsawatson »

Mark & Keith - thank you very much for your help and advice, and yes - that is exactly the article I was after.

Thanks very much again!

Ryan
Ryan Watson


Post Reply