Brake Light Switch Test

[Jeeps4Brains]

Is there a way to test the brake light switch while not mounted on the master reservoir?

I hooked a meter up to the leads and took a small drill bit and gently pressed into the fluid hole but nothing happened. Didn’t press really hard as I was not sure if this would screw up a diaphragm or not.

[Cacti_Ken]

You might damage the the switch if you force a probe into it. However If I recall it is a small hole. You could connect to your air compressor.
I haven't tested one to see how much pressure it takes to actuate one though.
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Tropical Veteran
35th Inf. Reg. "CACTI" 4th I.D. VN
Amateur Radio K5XOM

[Jeeps4Brains]

You are right I hardly put any pressure on the drill bit as I was worried I would puncture the diaphragm.

I talked to someone today that said the same thing you did and suggested I try stepping up air pressure to about 100psi.

Then there is the issue of it being the old switch and who knows what gunk is up inside there.

[Jeeps4Brains]

Here is what I did.

It turns out the cheepo air blow off nozzle I have, if you unscrew the tip, the size and threads are the same as on the brake light pressure switch. So I screwed the switch into the handle of the blow off nozzle. Then I opened the air valve to the line and pressed the valve on the nozzle. I had the ohm meter plugged into the switch. The switch didn’t close until I got to 120 psi. Dose that seem like the correct pressure for the break switch to operate at?

[wesk]

That should be close enough. The pressure supplied by your foot would be in the 150 to 300 PSI range.
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Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

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