Troubleshooting a brake relay

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=55816
Printed Date: May 04, 2024 at 2:33 PM

Topic: Troubleshooting a brake relay

Posted By: u352
Subject: Troubleshooting a brake relay
Date Posted: May 16, 2005 at 8:09 AM

My trucks brake light relay is attached to the master cylinder and before I disconnected it I wanted to test to see if that was the source of the problem. There are two leads going to the relay. If I jump the relays by connecting a wire to them should the brake lights come?

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Thomasd

Replies:

Posted By: Hornshockey
Date Posted: May 16, 2005 at 5:47 PM

If there are only two leads running to it; it is most likely not a relay. More than likely just a momentary switch. One of the leads should read 12vdc all the time, and the other should read 12V when the brake pedal is depressed, This is probably the easiest way to test; but jumping the two leads accomplishes the same thing.

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Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.

Posted By: u352
Date Posted: May 17, 2005 at 6:58 AM

So if the jumper didn't illuminate the brakes then the problem is up stream. I tried to test the switch last night and when I depressed the brake pedal I got a reading with a meter(continuity) so I assume that the switch is good. Problem must be upstream. The saga continues so thanks for the help.

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Thomasd

Posted By: Hornshockey
Date Posted: May 17, 2005 at 11:21 AM

does one side of the switch have a constant 12V?

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Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.

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