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Old 01-06-2019, 05:48 PM
86911TLCAB 86911TLCAB is offline
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Default Brake pressure switch question

1982 911 sc

Both My brake lights have recently stopped working. The brake light on the dash has also lighted up and won't go off. When I check for voltage I don't appear to have any voltage coming out of the switch ( have only tested the front most switch so far). Will the system work with one bad pressure switch or must both be operational for the system to work properly? Thanks.
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Old 01-06-2019, 06:51 PM
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Quote:
Originally Posted by 86911TLCAB View Post
1982 911 sc

Both My brake lights have recently stopped working. The brake light on the dash has also lighted up and won't go off. When I check for voltage I don't appear to have any voltage coming out of the switch ( have only tested the front most switch so far). Will the system work with one bad pressure switch or must both be operational for the system to work properly? Thanks.
It should though Iíve had both switches go bad. One goes bad and you donít know it till the othe ones doesCheck the fuse if you havenít done that yet
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Old 01-06-2019, 06:54 PM
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I guess you don't know until the second one fails. Have checked the fuses and continuity. Ordered a couple of switches. I suppose everything has a shelf life. Thanks Dave.
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Old 01-16-2019, 02:13 PM
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changed both switches...system operating...
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Old 01-16-2019, 02:19 PM
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Originally Posted by 86911TLCAB View Post
changed both switches...system operating...
Those switches go bad all the time. I've gone through at least 4 sets. I wonder if track use and repeated high pressure cycles in the braking system has anything to do with it?
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Old 01-16-2019, 02:27 PM
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i saw a mod for adding in a mechanical switch...seems pretty easy to do...may add it in...
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Old 01-16-2019, 04:12 PM
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I suspect it's running the entire brake light current through the switches and that is what is frying them. Even two in parallel can't take it. I've replaced several sets myself.
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Old 01-17-2019, 07:25 AM
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They work in tandem. If one fails the dash light should go on. In addition to the brake lights they are set up to light the dash when one brake fluid loop develops less pressure that the other. Clever design, Poor build of the pressure switch.
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Old 01-20-2019, 04:08 PM
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For the moment they are functional. Dash light has gone out. Brake lights working. Let's see how long the switches last.
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