John has a point, what is the cause of break pressure switch failure and does it have something to do the use of DOT5?
In my case the new switch worked quite well in its DOT 5 environment for many years before I was informed at a stop light that I had no brake lights. Returning home, I found that by pressing on the peddle very hard, I could get the brake lights to light. Since I very seldom, if ever, actually observed MY brake lights, I can’t say whether the condition came on quickly or the lack of light response got progressively worse over an extended period. I can say that now I look for a brake light reflection every time I back my Healey out of the garage.
So, did the switch fail because:
- It could not handle the electrical draw and deteriorate to failure?
- It becomes less sensitive and the softer peddle produced by DOT 5 (as compared to DOT 3) exposes the growing unresponsiveness sooner?
- DOT 5 deteriorates a component in the switch which results in switch failure?
Let me first state that I have no idea what the actual cause of brake switch failure is, however, if the above list has any validity and #1 is the culprit, then installing a relay would reduce the power through the switch and extend its life considerably. If #2 or #3, or a combination, are the cause of the switch failure, then the installation of a mechanical switch seems, to me, to be the alternative.
Pete, I totally agree. Although I replaced the pressure switch, I wired a mechanical unit in parallel with the hope of not having 2 failures. Since then, at least 1 switch has provided good break light response. I have no idea, however, if one or both are delivering as I have never again checked.
Ray (64BJ8P1)