brake lights

2002 MERCEDES BENZ ML320
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GASANDERS
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My brake lights stay on "bright" any time the key is on regardless of brake peddle position. Pumping the peddle and tapping the brake switch will not put them out. Cruise control is inop as a result!

6 cyl All Wheel Drive Automatic 112500 miles
Mar 19, 2010 at 6:33 PM
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CARADIODOC
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Check the switch by the brake pedal. It could be out of adjustment or the bracket could be loose or bent. Try pressing the button in by hand to see if the lights go out.

caradiodoc
Mar 19, 2010 at 7:03 PM
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GASANDERS
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Brake peddle switch is tight and properly positioned. It depresses/releases ok and I can hear the gear shift sylinoid clicking as I work the switch with my finger...brake lights stay on bright at all times with key on regardless of brake switch position.
Cruise control will not engage when driving with brake lights on bright.

[quote:e646795cbc="caradiodoc"]Check the switch by the brake pedal. It could be out of adjustment or the bracket could be loose or bent. Try pressing the button in by hand to see if the lights go out.

caradiodoc[/quote:e646795cbc]
Mar 19, 2010 at 7:39 PM
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CARADIODOC
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Can you unplug the switch and see what happens?

caradiodoc
Mar 19, 2010 at 9:59 PM
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GASANDERS
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Unplug switch and the Brake lites go out. the switch has 2 plugs, 3 wires each plug. The system also appears to have a relay in the fuse box that puts the lites out when it is removed/unplugged.
Mar 20, 2010 at 6:48 AM
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CARADIODOC
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We can eliminate the relay since it turns off by unplugging the switch. Plug them back in one at a time to see which one causes the lights to turn on again. I would be tempted to pop it apart to see if the contacts are arced together or if a return spring is broken. It any rate, I think you found the problem and it's going to have an inexpensive fix.

caradiodoc
Mar 20, 2010 at 5:18 PM
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GASANDERS
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Thanks; problem solved and lites work normal now. Gary


[quote:5523f1861c="caradiodoc"]We can eliminate the relay since it turns off by unplugging the switch. Plug them back in one at a time to see which one causes the lights to turn on again. I would be tempted to pop it apart to see if the contacts are arced together or if a return spring is broken. It any rate, I think you found the problem and it's going to have an inexpensive fix.

caradiodoc[/quote:5523f1861c]
Mar 20, 2010 at 6:26 PM
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CARADIODOC
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Dandy news. Were you able to fix the switch or did you have to replace it?

caradiodoc
Mar 20, 2010 at 10:53 PM
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GASANDERS
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just replaced it! thanks


[quote:cce952eaef="caradiodoc"]Dandy news. Were you able to fix the switch or did you have to replace it?

caradiodoc[/quote:cce952eaef]
Mar 21, 2010 at 6:00 AM
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Mar 29, 2010 at 2:17 PM
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