2005 Chevy Avalanche - The truck is in park, shut off, and the keys out. The brake lights are staying on. What do I need to do to get them to turn off?

There is a sensor or switch on the Park brake assembly that tells the ECU, (the cars brain), if the park brake is on or off. Your vehicle is assuming the brake is on and is warning you with the light and the beep. The simplest way to shut it up is to repair the park brake.

The parking lights staying on and the left turn signal not working may not be related, the turn signal is probably a burned out bulb, turn on the left signal and see if all the bulbs light up if not replace the burnt one, if they all light, the turn signal flasher may be at fault ( it can work with one side and not the other), as far as the parking lights staying on, check the door "pin" switch that controls the interior lights (are the interior lights staying on too?), since the chimes are staying on even with the keys on , I would suspect the door pin switch, probably the drivers side. I believe there may be a timer on the parking lights that turn them off after several seconds after the door is closed, this may be at fault if not the pin switch. newer cars and trucks also leave the reverse lights on for a while after the door is closed.

1. Disconnect the Brake Pressure Differential Switch located on the Combination Valve Assembly. It will have a Purple and a Black wire.

2. Turn the key on, engine off. If the problem is no longer present, replace the Combination Valve Assembly.

Could be your coolant temperature sensor is faulty,here's a link on how to replace.

was the electric brake control module professionaly installed? first check the ground behind the module and make sure it doesnt share the same one as your heater. too much current on a poor ground can cause both circuits to quit working.

no jack up and secure truck remove wheel- brake caliper-mounting bracket and brake disc under drivers side door by frame rail is a 1 into 2 cable with an adjuster this is e-brake cable loosen connection on 1500 models the brake is secured at bottom with a screw and a clip

See if the turn signals work,and the flashers,the problem,is most likely in one of the flashers,they are stuck,the flasher.

There is a brake light swich along the brake peddle that need's to be adjusted. Quick and easy fix.

It is Possible that the Brake light SWITCH is STUCK or Missadjusted Check this it is Located ABOVE the Brake Pedal

THE EBCM IS BAD this is the electronic control module that is on abs pump. you can replace seperate I think it is around 500 for part