Ok I think I found the problem

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Jul 5, 2020 | 06:53 PM

jerryst

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Ok I think I found the problem

I have had a problem with rear tail light staying on. I just rewired my truck with ez wire 21 circuit harness. The problem is rear left tail light stays on all the time. But when you use turn signal for left it flashes. I think I have narrowed it down to bad new brake light switch. With brake off I get power coming out of both connector. But when you take plug off you only get hot on one terminal. Can someone verify that I’m not supposed to get power out of both terminals. Also the hazard light don’t work. So I am confused
thanks
jerry

Jul 5, 2020 | 07:20 PM

hooler1

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From: Mason City, Iowa

Hey Jerry,

Do you have an ohmmeter? This would tell you if the switch has constant continuity with the wiring disconnected from it.

Jul 5, 2020 | 08:33 PM

jerryst

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I have a multi meter. I touch one probe to each post on the brake light switch? When I put test light on ire disconnected from brake switch I have one hot and one cold.
thanks
jerry

Jul 5, 2020 | 09:27 PM

hooler1

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Joined: Sep 2010

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From: Mason City, Iowa

Quote:

Originally Posted by jerryst

I have a multi meter. I touch one probe to each post on the brake light switch? When I put test light on ire disconnected from brake switch I have one hot and one cold.
thanks
jerry

If I am understanding you correctly, when you disconnect the two wires from the brake light switch you see battery voltage (measuring from your chassis ground) on one but not on the other. Is that right? If that is what you have then that is correct. Now put your multimeter in OHMs using the lowest resistance on the selector if the meter offers you a resistance range. Temporarily touch your test leads together. You should have almost Zero resistance. Next with no wires connected to your brake light switch, take those two test leads and now put them on your brake light switch. If you see close to Zero ohms again you know your brake light switch is "closing" and making connection through it. As long as there is no mechanical reason it is "closed" then yes it would appear you have a bad brake switch. Try this..
Remove it from the master cylinder or brake line tubing Tee and test it with your multimeter in Ohms again. Still have close to Zero Ohms? If so that's a bad switch. Let us know what you find

Jul 7, 2020 | 05:04 PM

jerryst

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Ok I found my problem with help from ez wire. It turned out to be a cheap stop light switch from cop brake light switch kit. Some stuff from cpp is good some stuff is bad. I guess I got the bad one.
thanks
jerry