I just finished setting this up: enter image description here

There are actually 4 lights chained together at the end rather than just one. Once I finished I turned the circuit back on and tried out the switches. All of them work as expected.

The only problem is the lights (all 4) will come on at full brightness for just a second then become very dim and remain there. What could be causing this?

EDIT: I did some more investigation. Everything works perfectly if I limit the wattage being pulled. It is currently working with 3 13W CFLs and 1 23W CFL. If I take out one of the 13W bulbs and put in another 23W or an incandescent light then the dimming behaviour returns. It's like there isn't enough power for all four bulbs.

This image belongs to do-it-yourself-help.com. The original wiring diagram can be found here: https://www.do-it-yourself-help.com/4_way_switch_diagram.html

  • I'd get a bulb with two pieces of wire attached and check starting from first switch, between neutral and various switch pins (depending on switch position, on some the bulb should light), and move to the right. But only if you are familiar with how to work on live electrical circuits and stay alive.
    – Dan
    Commented Feb 22, 2015 at 18:06
  • 5
    Ummm probably wouldn't listen to Dan...
    – DMoore
    Commented Feb 22, 2015 at 19:18
  • What type of lamps/bulbs are they? Are they ballasted fixtures? Commented Feb 22, 2015 at 22:27
  • Very interesting question. I updated the question with more information.
    – tgrosinger
    Commented Feb 22, 2015 at 22:56
  • When you say "There are actually 4 lights chained together at the end rather than just one.". Are the 4 lights connected in parallel, or series?
    – Tester101
    Commented Feb 26, 2015 at 12:10

2 Answers 2


I determined that my power source was no good. I don't know exactly what is going on, but it seems to be coming from a switched outlet system in another part of the house.

Easiest solution, tie up the old power source and find a different one that is cleaner. I found another circuit nearby that was barely used and is actually more spatially related to where these lights were being installed. Other than that the wiring was correct and works great.


I would double check the 3-way and 4-way switches.

I put some in my home and the diagrams did not always match the posts on the switches.

For example, in your diagram both hot terminals are on the left. Some switches have both hot terminals on top, or one top left hot and one bottom right hot. Different makers have different designs.

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