I have two dimmer switches that have started malfunctioning. They are in the same box with two other standard switches. Each controls a set of three small flood lights. There is no other way to control these floods except with the dimmer switch. They were working fine last week. Now, when I slide the dimmer, it sometimes works and sometimes doesn't. I know it isn't a circuit breaker problem since the other switches are on it as well and they work. These were installed about 6 years ago. I will need to call an electrician to fix this but would like to have an idea, if possible, of what the problem could be.
Electrical – Why are the dimmer switches malfunctioning
dimmer-switchelectrical
Related Solutions
That sounds like a short to me, and a potential fire or electrocution hazard. Leave the breaker off while you fix this. With a 3-way light switch, you'll have two possible paths between the switches (which is why there are 3 screws + ground, 1 line/load, and 2 switched). My guess is that one of the two switched wires is grounding itself. Remove the switch that you worked on, and see if the ground wires are coming into contact with any other wires.
Sounds to me like the white wire is the ungrounded (hot) conductor, and should be reidentified as such using a bit of black tape/paint/marker. Power comes to the first switch via the white, and then to the second with a white jumper.
The red wire is the switched "hot", which is used to control one light. The black wire is the other switched "hot", and is used to control the other light. The bare wire is ground.
To install two new switches:
- Turn the power off, and verify that it's off.
- Mark the white wire with a bit of black tape/paint/marker.
- Connect the white wire with two short bits of black wire (pigtails), using a twist-on wire connector.
- Connect one black pigtail to one switch terminal, and the other to one of the switch terminals of the other switch.
- Connect the red wire to the other terminal of one switch.
- Connect the black wire to the other terminal of the other switch.
- Using bare copper or green pigtails, connect a ground wire to the green screw on each switch, and the box if it's metal.
When done, it should look something like this.
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Best Answer
Sounds like a simple case of a bad switch.
Note: a squirt of WD-40 into the right place in the sliding mechanism can help, or even fix the problem at least temporarily by lubricating the internal sliding electrical contacts. But getting the location right requires experience, and if you have to bring out an electrician anyway, they'll prefer to replace.
Do this with the power off by the way. And it's far better to take it apart and lubricate, compared to the squirt and hope method.
Consider upgrading to a dimmer model with a remote control, CFL compatibility, or other features.