Brake lights come on and stay on. Car is grounded somewhere. I don't know where to look

Replace your brake switch on the pedal. If problem continues you have a bad ground somewhere

Sounds like a short on the wire to the brake light switch on the brake pedal. This switch connects the brake circuit to ground to turn the lights on, if the wire is already shorted to ground (metal on the body somewhere) then the light will be turned on even without the switch.

bad earth or the wrong bulb in the back lights but to answer correctly i would need to know the type of lighting system used and make and model of car ,as american cars do not have a seperate indicator but the brake light flashes .Your ECM is ok and whoever told you it was faulty is not a proper mechanic ,iam sure you have the wrong bulb in ,like a single pole instead of a twin pole bulb .

ABS light on did they check codes ? The light staying on an no codes is usually a insturment cluster problem not the EBCM - electronic brake control module . No relay in side the module , a transistor or diver as they call them . This transistor will supply a ground on a electrical circuit from the brake lamp driver module ,when it does this the brake lamp driver module ground a electrical circuit for the ABS light . If anything is bad causing the ABS light to stay on it would be the brake lamp driver module . Your best bet ,take it to a GM service dept.

its a bad earth somewhere , crossed with life , auto elecrian is what u need unless u can find it yourself

{: ) Looks like your lightings got haywired. Have you had vehicle repairs recently? Anyway, it seems that you have poor grounding connections for the affected lightings. Some circuits share common ground, and ground terminals are strategically distributed on the vehicle. If these grounds don't have good contact with the body, chassis, or engine ground, circuit functions are badly affected. Thats why these ground points should be inspected and kept clean and tight, maintain that good wire and terminal contacts.
We can start with G100 located at the Left Front of the Engine Compartment on the left front body mount. See diagram below:


Check out also G401 which is located in the chassis harness, mounted to the left rear Body mount. This ground point is shared by the rear lamps like the brakes, reverse, and rear signal lamps.
If possible check also other ground points that you may visually come across while on your search. Be sure also that fuses are all inspected good.
I hope we get lucky in finding and fixing a certain lamp function, if not all. Goodluck.

If the brake light switch is causing the problem then unplugging the switch connector should make the lights go out. If they don't go out, then a short to ground somewhere in the wiring harness is indicated. If this is indicated, then trace the harness from the switch to the brake lights. A common problem area is underneath the door sill trim panel. Removing it and performing a visual inspection is usually a good place to start looking.

Check brake switch and relay.

Please see my tip at http://www.fixya.com/cars/r6053280-lights_out_lights_not_out_bulbs_ok and let me know if you have questions.

G100
Battery cable, negative cable, RH side of engine compartment to the RH frame rail
G101
Left side of the radiator support
G111
Top right of the engine, below the ignition control module
G113
Lower LF of the engine, on the automatic transaxle stud, near the starter
G151
On the left frame rail, forward of the left front strut tower
G171
On the left frame rail, right of the left front strut tower, rear of G151
G201
Behind the I/P, on the LH side of the brake pedal bracket
G202
Behind the I/P, in the center
G203
Behind the I/P in the RH side of the brake pedal bracket
G301
At the base of the LH B-pillar
G302
At the base of the RH B-pillar
G309
On the RH side B-pillar

Sounds like a broken wire somewhere.
Since the middle brake light works I would suspect it is somewhere in the trunk or close to the back seat.
Buy or make a tester. A 12v light with a clip on one wire that you clip to a good ground on the car the other wire with a sharp point. Turn the turn signals on then poke wire to rear lights until tester lights. When tester lights you know the break is somewhere inbetween the tester and the brake lights.

Hope this helps.

Stan