If the lights work only when you really stand on the pedal the switch has failed, could be dirty contacts but I dont know of anyway of servicing them. Just replace it and solve the problem the easy way.

Tony

Posted by: @txmanager-2-2-2-2

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'38 Master Deluxe - 6v

When I put A LOT of pressure on the brakes, the lights work.  What does the brain trust say...bad switch or gunked up? 

I put a number of new pressure switches on my 38. Eventually they all succumbed to having to stand on the pedal for my brake lights to work. I got fed up with replacing the switches so I converted my 38 to a later lever switch. I ran short jumper wires to the terminals on the pressure switch to complete the circuit. The lever has a piece of hose on it to fine tune the point where the lights come on.

Brandon,

I'm sorry I did not see your post until now.

I had a premature failure of a switch, on my 1936 truck. I had seen several posts here that were along the lines of what Tiny has posted. My new switch was purchased at O'Reilly Auto and had a warranty so I thought I would try another one before going with the mechanical switch conversion. That was 10 years ago, or more, and switch number 2 is still working fine.

Mike 

@35mike Wow! That's outstanding Mike! I was going through one a year. It's been long enough now I don't remember where I was buying mine.

I found some "old stock" ones on eBay and got a couple of them, thinking the problem with the new ones might be that they were made China. I fully expected that I would be installing one of them within a few months. 

Mike

Failure of the pressure activated brake light switches is a known problem with silicone brake fluid. If you don't have silicone fluid then they might be faulty switches.

@tiny Are you by chance using silicone brake fluid? I am under the impression that was the culprit for so many failures. I was changing my switch yearly, so I went to a mechanical switch approx 20 ago. No more problems!

Nope, I'm using DOT3. I never disassembled one to diagnose the issue. I assume it's the result of inferior materials used in construction and possibly corrosion caused by DOT3's propensity for retaining moisture in conjunction with said inferior materials.

I’ll add another dimension to the conversation.  I believe the current day pressure switches are built with different actuating pressure specifications depending on the manufacturer even thought they may look the same externally and are listed for our vehicles. I also believe current day switches are likely designed for the  “one size fits all” application.  I’ve found that installing a universal switch specified for low pressure to be more reliable.   Your FLAPS is unlikely to know what pressure their switch activates at.  Universal low  pressure switches are sold at places like JEGS and eBay however.

Minetto you could well be right though I have not tried to find the operating pressure of any available switch.

Tony