How to find which 3-way or 4-way switch is bad?

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  #1  
Old 09-08-11, 02:00 PM
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How to find which 3-way or 4-way switch is bad?

We have our foyer ceiling lights that are controlled at multiple locations (6 to be exact). Over the past few evenings, the switch at the base of the stairs to the second floor does not turn on the lights unless another switch is turned on first. We have done no electrical work, so one of the switches must be malfunctioning.
Is there any way to tell easily which switch it might be without removing each one and replacing one at a time?
We have 4 4-way switches and 2 3-way switches. They are Decoras, and the 4-ways don't seem to "click" as completely as the 3-ways, if that makes sense. So I'm thinking it may be one of the 4-ways.
Thanks
Dave
 
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  #2  
Old 09-08-11, 02:06 PM
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You've gotta test them one at a time, although the problem switch is most likely the second floor stairs one you have been having trouble with. I'd have to think about it a little more, but I'm pretty sure it has to be that one based on the way you've described the problem.
 
  #3  
Old 09-08-11, 02:16 PM
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The fix may be nothing more than attaching the wires on the switches to the screws on the sides if they are currently back-stabbed into the back of the switches. Unfortunately, there are 6 to do, and it won’t guarantee that will fix it, but it eliminates a common wire connection problem. If it doesn’t fix it, then you’ll have to test them one at a time, as Ben said. I’d also start with the one at the base of the second floor, but it may not necessarily be the culprit. Could be the one in line before or after it that has the problem.
 
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Old 09-08-11, 03:37 PM
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I would start with the ones that are used the most.
 
  #5  
Old 09-08-11, 04:04 PM
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Try this, the bad switch will have one position where none of the other switches will work.

Corrections welcome.

Bud
 
  #6  
Old 09-08-11, 04:12 PM
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Originally Posted by Bud9051 View Post
Try this, the bad switch will have one position where none of the other switches will work.

Corrections welcome.

Bud
I guess it's worth a try. I know the usual scenario is the one at the base of the stairs on the first floor will not turn on the lights at night. But at least 2 of the switches in the upstairs hallway will even with the one downstairs not working. If I turn any of those 2 upstairs switches on, the downstairs switch works....until the next evening, it seems.
 
  #7  
Old 09-08-11, 04:47 PM
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Dave, my confidence level is shrinking that this will be a conclusive test. Power passes from source to light via all of these switches. If there is a poor connection or bad switch, when that path is selected and the connection is not made, nothing will work. Where my confidence is weak is the problem could be the switch/connection feeding the one that appears to be bad, a loose wire on one end is no different from a loose wire on the other.

As ibpooks said, may take some more thinking. But trying it might be informative.
Bud
 
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Old 09-08-11, 05:00 PM
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Thanks Bud. I'll give it a try and report back. We tend to use the 1st floor and 2nd floor switches 90-something percent of the time, so zi'll check those two first as they get the most wear and tear.
 
  #9  
Old 09-13-11, 05:05 AM
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A little more info....the switch at the base of the chairs (1st FL) was not working yesterday. I went and tried each of the other 5 switches. They all worked. I turned the 1st FL switch on/off....no lights. I then did the same for the other 5 switches (on/off). Each time, the lights worked. After testing all of the switches, the one on the 1st FL worked. Two hrs later, it still worked.
I'm thinking this rules out the 1st FL switch as defective. What I will try today is again turn the 1st FL switch on/off. If it does not work, I will do that to each of the other switches one at a time and each time go back and test that 1st FL switch. My thoughts are the defective switch will reveal itself when the 1st FL switch starts working after manipulating the defective one.
Does that logic make sense? Thanks. Dave
 
  #10  
Old 09-13-11, 06:13 AM
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Hi Dave, I was hoping you would report back. I played with the logic and only part of the diagnostics can be conclusive. The two 3-way switches can be tested with the logic where in one position all other switches will work in all combinations and in the other position no lights from any combination of the other switch. If you get a light in any combination in both up and down positions of a 3-way, that switch is good. If it meets the above "all or nothing" test, then that 3-way switch OR the wire from it to the first 4-way switch connection is bad OR that first 4-way is bad. In other words, if it meets the all or nothing parameters it may be the 3-way or the wire connection to the next 4-way or an internal contact problem of that 4-way.

If it is intermittent, catching it will be a problem.

I have continued the thinking for some logic to diagnose the 4-ways, but so far a conclusive test evades me. If you know the wiring sequence, 3 to 4 to 4 to 4 to 3, then the some additional testing can narrow it down a bit, but because a bad contact at a back stab connection cannot be isolated from a similar problem from the preceding switch nor a similar contact problem inside a switch from the preceding switch, pinpointing the exact location seems impossible from just flipping switches. Even though I enjoy solving logic type problems, I think if it can't be isolated by the initial 3-way test, then I would go with the prior suggestions to swap out the most likely high use 4-way and so on.

Let us know,
Bud
 
  #11  
Old 09-13-11, 06:29 AM
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<Opinion> What is more important to you, fixing it or spending days trying to run down the problem? Fact with five switches and age more then one may be bad meaning even if you replace one bad one you may still have a bad one. That could fool you into thinking you had not replaced a bad one. Is it worth $15 to you to fix this problem and be done with it? Five new switches of good quality would only be around $15. Replace all and you know it is fixed for many years with any luck. Replace one and who knows when the next old almost worn out switch will go bad.

Caution: If you replace all test throughly after installing each switch to be sure you wired it correctly.
 

Last edited by ray2047; 09-13-11 at 06:47 AM.
  #12  
Old 09-13-11, 06:30 AM
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All it would take would be for one of the switches to have a traveler switched somewhere and the switching would not work properly. Perhaps someone flipped a switch that had not be used before and created the issue.
 
  #13  
Old 11-23-11, 06:07 AM
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Originally Posted by ray2047 View Post
<Opinion>Is it worth $15 to you to fix this problem and be done with it? Five new switches of good quality would only be around $15.
$15 total? A single 4-way switch can cost $15 at local hardware stores. Where can you get 5 for $15?
 
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Old 11-23-11, 07:50 AM
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Originally Posted by jrwalte View Post
$15 total? A single 4-way switch can cost $15 at local hardware stores. Where can you get 5 for $15?
Dang! Your right. My Pricomatic is stuck in 1950.
 
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