S3 brake light pressure switch reliability?

[klev]

I've just recently replaced the in-line brake light actuating switch. This is the switch with the two spade lug contacts that is mounted to the frame. (There is no pedal-activated mechanical switch.)

Lately the brake lights will not come on unless I use a great deal of pressure on the pedal - not a safe condition. Should I replace the switch again? It has been less than 1000 miles/ 18 months since I mounted it, no idea how long it was on the shelf prior to my purchase. Did I install a faulty part?

I don't want to replace it and not solve the problem. However, if the switch is the only possible source, I'll change it out.

Any thoughts?

Thanks and Happy Motoring

[1964 S1]

I ALWAYS go for the easy way first. I'd check the brake bulbs in their sockets, clean things up a bit, check for tight fit. If that doesn't help, I'd check all the ground wires connected to this problem. Then. . .

[miked]

Have not exepeiernced the pressure type switch but...

Have had trouble with plus twos and baby elan. Both myself and my friend have fitted a relay in this circuit to reduce the current that the switch has to deal with. 2 x 21 watts divided by 12 volts is 3.5 amperes. IMHO whilst the switches are new and clean and correctly lubed they are ok. But the nature of braking and teetering with the pedal seems to rip and burn the surface. I have stripped and cleaned many a switch that is so called duty rated. The relay seems to click away reliabley doing a better job since it is designed with a contact cleaning wiping action and deals better with the job. Others may disagree on the basis of adding another component in the system but it works for me. Plus I can hear the beastie (relay) at tick over so have constant reasurance that it is working as I depress the pedal. You could also add a small lamp/led to the relay out put to see it is giving output.

Mike

[klev]

Thanks for the replies.

Happy Motoring!

[types26/36]

Klev,
Disconnect the two wires from the switch and join them together, if the brake lights come on then the problem is the switch. I had the same problem in my Seven, the brake switch would only last a month or two and I had to replace it. After about 3 or 4 switches I changed from silicon brake fluid to normal brake fluid and no more problems, if you are useing silicone fluid I suggest you either use normal brake fluid or you fit a mechanical type switch.
Brian.

[Dave-M]

Just a thought, If the switch is mounted vertically it may have some air trapped in it, Air will compress ie. high pedal pressure required. Maybe???
Thousands of cars used this system with no problem, so it should present no problem on an Elan.
Regards
Dave-M

[klev]

Thanks for the brainstorming. I've only just now got some free time coming up to get back on this problem.

We know the switch works, because the lights do come on - only with very hard pressure on the pedal. If it's air, normal pedal pressure should illuminate the brake lights eventually if I keep my foot on the pedal. I'll try that.

If it's ground or poor contacts in the fixture or the wiring, I'll track it down.

Cheers and Happy Motoring