Kate
You changed the lamps in one room and your dimmer fails to dim and then you changed the lamps in your son's room and a different dimmer fails to dim those lights too?
How many lamps are on each dimmer and what is the combined wattage (add the watts of each lamp together) for each dimmer. ie if you replaced the 3xhalogen lamps with 50w lamps then you have a combined load of 150w.
Do your lights work at all with the dimmer switches. Do they just fail to Dim but come on and off?
Matt, January 2009