I had a rotary dimmer that worked fine when i installed a new trademaster rotary dimmer the dimmer didn't light up and the light dimmer didn't work

Switch could be prob, check fuses first.

most likely the type of lamps/bulbs you have are not compatible with the dimmers.

Rotary dimmers are not normally suitable for fan control plus not all types of lamps are dimmable , so used wrongly a dimmer could catch fire.
Steve

if the indicator light on your dash appears to be working, you probably just need new bulbs. No, they didn't both burn out at once. You probably drove a while with one headlight and didn't know it. If the indicator light doesn't come on and off, you will need a new dimmer switch, but since they work on bright, I am assuming that works.

If you want two fixtures to be operated by the same dimmer, it is easier to just connect the fixtures together by twisting leads together and then wire nutting them and then run one set of leads to switch. That way you meet all codes.

Is the dimmer rating higher than the load? Are you trying to dim fluorescent lamps? A flourescent requires special dimmer switch.

If you over loaded or mis-wired a transistor or wire wound dimmer, you may have damaged it.

Is this a three way light circuit?

Hi,

You will always have voltage through the black incoming wire unless you turn your circuit breaker off. This wire will be attached to the common terminal on the switch. Is this what you were testing?
The power comes in the common terminal and then is switched through, or on, and broken, or off, when the dimmer is clicked. Therefore, there is always power coming into the switch.

Hope this helps, if it does, please place a vote for me. Thanks,

Handie Andie

Install one dimmer at the load end feeding the light. Install a standard 3way switch at the other end. Make sure the dimmer switch is rated for the type of bulbs in the fixture. ie Led, halogen etc.

1) Electronics inside dimmer can go bad, and lights will not work as before.
Simply replace dimmer.
I buy new dimmers at Home Depot.

2) Lutron shows a wide variety of dimmers:
Use pictures from page to identify type of dimmer you want, and then google search: For example search for 'skylark dimmer' or 'rotary dimmer'
http://www.lutron.com/Products/StandAloneControls/Dimmers-Switches/Pages/DimmersSwitches.aspx

3) Add a comment for more free help. For example how to install new dimmer without calling electrician.
Also take advantage of fixya phone service.
For a price, fixya expert speaks with you over phone while you work on dimmer, or any do-it-yourself project.

With 3-way dimmers, you have to buy a dimmer-and-companion-dimmer combo.
The two dimmers communicate with each other

http://www.amazon.com/Smarthome-2494M3-SwitchLinc-INSTEON-Dimmer/dp/B000I68DWI