Hello I have problem I honestly don't know what to do
My car rear brake light stuck on when ignition is on I thought it's the brake switch so replaced it but it didn't solve the issue still the rear lights on brake all other lights working fine
I removed the rear relay too and still on
I noticed I can shift from park without pressing brake pedal I removed the brake switch itself and the rear lights was still hold on brake !
What could cause this problem and where I must check ?

2001 silver jag xj8

 

Are you having a problem with all of the brake lights lit up or just one staying on?

 

Both side are on brake when the ignition is on

 

Does the third (high mount stop lamp) brake light work normal? Excluding the brake switch, have you changed any of the tail light bulbs at all recently?

 

Wait, you removed the relay and the brake lights are still on? Lets make sure you removed the correct relay, the one you want is in the trunk in the cubby between the battery and the rear of the trunk. Looks like a T on its side. The stop light relay is the third one in the row across. Pull that and see if your brake lights are still on. I'm hoping you maybe pulled the wrong one and that your stop lamp relay is shorted. If this does turn the lights off, try swapping in the one for the rear window defroster (heated backlight) and see if your brake lamps work properly.

 

I know what I was doing

 

I bought the car without 3rd light brake
I think this take us to the SLCM ?

 

Before you start digging into the SLCM, pull both brake light bulbs and make sure everything is ok with them first. I’ve seen all kinds of weird crap with misinstalled bulbs, completely wrong bulbs, water intrusion, etc.

Have you spilled any fluid in the J gate or performed any work in or under the J gate recently? The reason I bring it up is because of the shift interlock comment you made earlier.
The gearshift interlock solenoid gets its power from the BPM. I wonder if the BPM is shorted to power and sending power to the interlock solenoid and SLCM for the brake light circuit when you turn the key on?

 

I have checked the bulbs and no rust nothing unusual
Also I didn't do any work around the J gate I hate to replace modules Im thinking to connect rear wires to the 3rd brake wires but I have no idea if the high Mount brake also stuck on brake or not I have to check it first hopefully it's working fine this way is simple fix will see what happens

 

BPM’s and SLCM’s are the two most common failures on these cars. I’m not saying to replace one or both but, just keep that in mind. The 3rd brake light operates via a stop lamp relay in the trunk fuse box. Relay #5 and #8 fuse 10am.