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What would cause the third brake light and rear window defogger to not work and the defogger switch light to come on when the brakes are applied?

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2015-07-17 17:43:05
2015-07-17 17:43:05

Sounds like you have an issue with a leaking vacuum line. Without knowing the type of vehicle, I'd say that there's a good chance that your power brakes are vacuum assisted. When you apply the brakes, you may be using up what vacuum you are still able to produce in spite of the leak. When you have a vacuum leak, it usually causes other problems, such as rough or otherwise difficult idle. It might be worth inspecting what you can to make sure everything is in place, with no lines cracked from age, or melted by laying against the exhaust manifold or exhaust piping, or, once I saw where battery acid had eaten through a vacuum line ran under the battery box. , Good luck. :-)

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