Brake lights

db6431

New Member
#1
Hi all
Got told I'd no brake lights today, checked bulbs and they are OK, so took the wires off the switch and touched them together and the brake lights come on. So great so far, looking like a new switch, but when I put my meter on the terminals at the switch and get my wife to press the pedal, the switch seems to be working as it should. Any ideas where I could check next, I've emeried (is that even a word!) the terminals but no joy.
 

roverp480

Active Member
#2
If connecting the wires together illuminates the lights , its got to be the switch despite getting a reading across it. If you just connect the feed from the ignition to the switch and operate it, do you get 12v on the output . It might have a very high resistance.
 

db6431

New Member
#3
If connecting the wires together illuminates the lights , its got to be the switch despite getting a reading across it. If you just connect the feed from the ignition to the switch and operate it, do you get 12v on the output . It might have a very high resistance.
Didn't check the voltage, just had the meter set to beep for continuity and heard a beep every time the pedal was pressed. I'll check the voltage tomorrow. Thanks for your quick reply
 

unstable load

Well-Known Member
#4
I've been caught out like that with the modern digital multimeters. The continuity setting is very sensitive and doesn't allow for high resistance through switches.
 

db6431

New Member
#5
Hi all,
Now really confused, advice as above makes sense so thanks for that, checked the voltage on one of the terminals after attaching the 12v supply and meter read 12.4v. Joined the two wires together and brake lights illuminated, attach them back to the switch and nothing. Going to crimp on two new connectors before I buy a new switch just in case
 

Tom W

Active Member
#6
I had a similar problem with my original brake switch. Turn out it had lost continuity where the terminals were riveted on. Every time I tried with the meter, I’d get a reading as I was pushing on the loose terminal and causing it to connect. When I refitted the wires, I’d get no brake lights as the weight of the wire pulled the terminal to where it wouldn’t make contact. A new switch cured the problem.

Modern repro switches aren’t great though, and don’t seem to last very long.
 

db6431

New Member
#7
I had a similar problem with my original brake switch. Turn out it had lost continuity where the terminals were riveted on. Every time I tried with the meter, I’d get a reading as I was pushing on the loose terminal and causing it to connect. When I refitted the wires, I’d get no brake lights as the weight of the wire pulled the terminal to where it wouldn’t make contact. A new switch cured the problem.

Modern repro switches aren’t great though, and don’t seem to last very long.
Thanks, new switch ordered, can only be what you say
 
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