Where can I find heating element to replace on my melitta kettle mek 17W???

SOURCE: Red light's on... but no hot water!

OK, inside the unit there are three items, the heating element, thermostat, and thermal fuse.What has happened is the element got too hot and the thermal fuse opened.There is no reset button.In some cases you may run across a defective heating element or thermostat but its not common.The fix would probably be replacement of the thermostat and thermal fuse.For this, you would have to contact a small appliance repair center in your area.

SOURCE: How do I clean the contact points between kettle and platform?

PROBLEM:

My problem was similar for the Cuisinart KUA-17.  I clicked down the on switch and it stayed down.  However, the light and power together seemed finicky.  That is, the light came on if I positioned the kettle in the base correctly, but then it sometimes went off without triggering the switch to pop up.  When the light went off while the switch remained down the water never boiled, but when I was lucky to position it such that the light remained on, the water did boil and the switch popped up ... as it should have.  It seemed to be getting more and more finicky and difficult to position correctly ... so I took it apart.
SOLUTION:
First of all, the base has screws that take a triangle screwdriver which I don't have.  So I found a small flat-headed screwdriver (like one you'd use for glasses) that just fit along one side of the triangle.  I was able to get three base screws out this way and since I expected to need to do this again in the future, I used my dremel to grind a larger flat-headed screwdriver slot in each.  It's been about a year and a half since I fixed it last time and this time I was glad I had the slots.
Once you get the plastic base off, you'll see the mechanics of the switch.  There are two wires that both turn on the light and power the heater element.  Where the wires connect to the switch mechanism, there are two metal tabs that stick out in opposite directions from the center.  When the switch is pushed down, you can see these two tabs move.  They are each moving to touch a contact and complete the electrical circuit.  My problem was they were not making a good contact.  The contacts are hidden behind the tabs.  All I had to do was bend the contacts one millimeter closer (i.e. as little as possible) so that they would make a good contact.  The only other trick was I had to remove the switch mechanism from the bottom of the kettle to do this.  Then I just used the same small flat-headed screwdriver to bend the contact as in the picture below.

SOURCE: Red light's on... but no hot water!

Just a bit of clarification; the lights and heating element are both downstream of the thermal protection ( I had mine apart and had a look). Therefore the lights would be off if the thermal protection had kicked in.
Lights on but no heat means element has a problem. Could be loose wire but more likely burnt out. If you have a tamper proof TORX bit you can take the bottom cover off and check for continuity through the element. Isolate the lights from the element so your meter is not accidentally seeing continuity through the lights.

SOURCE: When the kettle is switched on, the light comes on...

sounds like the element has died. If it's still under warranty, take it back. If it's not under warranty, contact an electrician or appliance repair person. Unless it's an expensive kettle though, it's probably not worthwhile fixing, as elements can sometimes be as expensive as a new kettle

SOURCE: MG32 Cordless Electric Kettle: Power light shows on my kettle but water does not...

sounds like there's water in the element. Empty it out and let it dry out completely for a few days, and then try it again.
If the element is a concealed element (ie- you can't see the coils when you open the lid up) then there's probably a water leak into the sealed compartment.
Contact the manufacturer for a recommended repairer.