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MG MGA - brake light switch

Has anyone had any experience with the Ron Francis low pressure brake switch?

Thanks, George
G Goeppner

Hi George

I have used Ron's low pressure switch. It's been installed now for over two years and it has worked without any problem. It's worth the price. I had used other aftermarket switches (more than one) only to see them fail in a relatively short period. I ordered an extra one at the time just to have it as a backup but have never needed to use it.

Bob Ravich

I've used them in several cars without issue. I've had only one go bad. They seem to be more reliable than the current repro Lucas units. About 50% more reliable in my experience. They don't look original at all and have a big plastic connector on top, in case that matters to you.
Steve S

Had one which seemed perfect for the first season.
Came out this summer and found I had to push like hell to get it to work.
Now resorted to a mechanical switch on the pedal shaft fitted by James at Bob West's. I believe its from an MGB.
Extremely sensitive and hopefully will last longer.
D C Grahame

I had a brake light switch from Ron Francis installed, and it functioned perfectly for the first seven months. After that my wife, who was following me in her car, informed me that my brake lights were not working. I tried them in the garage and noticed that I had to push mightily hard on the pedal to get the lights to come on. I connected a relay to the switch, and now they are working just fine, just a light touch on the pedal and the lights come on instantly. I found the relay circuit on a website on the net. Can't remember the website but if anyone is interested I can easily find it and upload it here.

F Camilleri

I run silicone fluid and I am now on my fourth brake presure switch. I will now be changing to an electrical swith that mounts under the an adaptor that mounts on the clutch/brake pedal bracket...and has the wires connected to the origional brake wires. I saw this in a Namgar mag and think it is the best solution. The one big problem, is getting at the bolts etc under the dsah, when I am not as nibble as I use to be.
Gordon Harrison

Just reviewing my maintenance records. I bought my MGA with 150,000 miles in 1977, restored it and put it back in the road in late 1986 (with the original brake pressure switch). I changed to DOT-5 fluid at the same time without replacing the switch. After that the switch only lasted another 120,000 miles (270,000 total miles in 40 years). The replacement switch is still hanging in there after another 130,000 miles in 16 years. I do not use a relay, just use a good switch.
Barney Gaylord

Mr. Gaylord,
I guess it is a bit like a good rotor in your distributor. Some are terrible and apparently the red ones are great. So be it with the brake switches. Problem is where does one find a good brake light pressure switch that works with silicone brake fluid.
Gordon Harrison

I bought mine from Moss, but parts from many years ago are not necessarily the same as today. Heck, in this fast changing world parts from yesterday are not necessarily the same today.

For this situation perhaps the best we can do is to keep reporting the failures, and try to buy a better part from some other source through process of elimination. I have been making a list of faulty parts reported for a couple of years, but so far reports of the sources are very few. It is just too easy to toss out a $9 part and buy another one (after the warranty has run out).

So now that we are back on this subject again, does anyone have a failed brake light switch and can report the source and purchase date?
Barney Gaylord

There are numerous reports of the MGB mechanical switches failing just as quickly, unless a relay is fitted.
Dave O'Neill2

The current Ron Francis web page for their brake light switch states that it is "silicone compatible", so perhaps the failures of the Ron Frances switch experienced by some are related to some other switch problem.
G Goeppner

The switch failures have nothing to do with fluid type. They fail because of bad contacts with high resistance that do not snap and will not carry the current required long term. Fluid will never touch the contacts.
Barney Gaylord

I have been told by a friend who runs a successful auto electrical business that modern brake light switches are designed to run with a relay and the full 12 volts causes them to burn out and/or prematurely fail.
Barry Bahnisch

If I then make the converstion to an electrical brake light switch,should I place a relay ...inline....between the switch and the wiring connection. OR, does it really matter.
Gordon Harrison

Modern brake light pressure switches are not designed to work with a relay, they are just not designed to work (trash product with faulty electrical contacts). Hard to believe they can't build a pressure switch that can carry 3.5 amps current for long term.

If converting to a mechanically actuated brake light switch, you should still not need a relay. The brake circuit with two 21-watt bulbs only draws 3.5 amps.
Barney Gaylord

Some people have jury rigged a mechanical switch to operate off the brake pedal(other than the system on later MGBs) using a standard micro switch. There doesn't seem to be a problem with those switches. Most of the brake light switches designed as such are the problem area and my experience agrees with Barney's (trash product with faulty electrical contacts). This could be a situation where the majority of new autos do use a relay with the brake light switch are designed to work with a relay. Most of the brake light switches on the market are all made by one manufacture - I want to say Cole Hersey, but I really don't remember for sure. Cheers - Dave
David DuBois

This thread was discussed between 24/06/2013 and 30/06/2013

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