ETS light..
 

ETS light was on a customers car.. One of the mechanics replaced a switch that was located under the steering wheel.. Can someone tell me what the switch is called and the purpose? Note: the switch that was replaced also affected the cruise control... Thank you..

I'm pretty sure it's a "brake switch" or something like that. It controls the brake lights and stops them from going on and off during ABS braking. It appears to be a pretty common failure. When it goes, so does the cruise control. don't know why.

Its actually called the brake light switch
 

Just asked the worker today, he told me the reason why the cruise control stops working completely is because you stop the cruise control via "the brakes" so if the brake light switch isn't working properly .. than your cruise control will be a dangerous situation in case there is a emergency.. This is also a very common problem for the ML's..

My ETS light is on and cruise control does not work. But my brake lights do work.

If it was the brake pedal switch, wouldn't the brake lights not work, or does the switch have multiple functions?

I think the switch is failing in the on position. That would disengage the cruise and the light would still work.

It may be the brake light switch, hold that thought though:
The brake light switch has 2 sets of contacts, normally open, or "NO", and normally closed "NC", they both have to work for the ETS to be happy, but only one set will cause the brake lights to fail (unsure which one) so it depends on HOW the switch fails as to if the brake lights will fail to work. It seems about 50/50 on which contact will fail, that's why it's important to check to see if the brakelights work or not with a failure light of this nature.
Other than that, there is a "clockspring" contact under the steering wheel for the airbags and I believe the horn wiring. The steering wheel angle sensor is down about 1/2 way in the column, and I believe to replace it requires a new upper steering column. The multifunction switch on the ML I don't believe will affect ETS, but the steering angle sensor sure as heck will. The multifunction switch includes the headlight switch, wipers, directionals, and hazard falsher, the cruise switch is a seperate item which does attach to the multiswitch. Maybe they left something unplugged, like the cruise switch. Not really enough info for a real good guess, but hopefully this will prompt some more dialog and I can give you a better guess.
Gilly