Steamer and milk frother not working

This sounds like one of several problems:
1. Does any indicator light come on? If there is one and it doesn't you either have a bad thermostat (size of a dime/1/4 inch thick) black item with two wires attached to the chamber or a bad heater. Check both with an ohm meter...Resistance of any kind across the terminals means okay.
2. Could be the switch. Same kind of test.
3. If you've got a steam leak, deal with that...new cap or valve.

Make sure all wire fasters are clean and bright. If screwed down, make sure they are tight. Cycle each connector off and on to clean them.

Remember: always work on your unit with it unplugged. You may need torx screwdrivers to open this unit. Any hardware store will have sets of these items.