How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Chris (aka-Moose) Your Own Question
Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Car
Satisfied Customers: 43933
Experience:  16 years of experience
Type Your Car Question Here...
Chris (aka-Moose) is online now
A new question is answered every 9 seconds

Land Rover LR3 V8 SE: I have a 2006 Land Rover LR3 that is

Customer Question

I have a 2006 Land Rover LR3 that is throwing error code p0504. All of the lights on the dash are illuminated. I have replaced the Brake Light Switch as well as all of the tail light bulbs. I also replaced the battery. The error is STILL happening. Any suggestions on how to fix this?

Submitted: 3 years ago.
Category: Car
Expert:  DaveTheCarGuy replied 3 years ago.

DaveTheCarGuy :

Hello and thank you for using

DaveTheCarGuy :

The possible causes of the P0504 code are: - Faulty stop lamp switch
- Blown stop lamp bulb
- Brake switch harness open or shorted
- Brake switch circuit poor electrical connection

Read more:

DaveTheCarGuy :

you should look for loose wires on the brake pedal sensor. Also, have someone depress the brake pedal and verify that all the brake lights illuminate.




These are things that have all been checked, so unfortunately this answer is not sufficient. The car will just be taken to Land Rover for evaluation.

Expert:  DaveTheCarGuy replied 3 years ago.
Hello, sorry you do not feel the answer fit your needs. One other thing to look at is the high stop lamp (at the top of the rear door). Sometimes the wires can break from the door opening and closing repeatedly. Does the high stop lamp work? If you need any follow up information, please let me know.
Customer: replied 3 years ago.

Unfortunately this vehicle is a bit more complex than that. The high stop lamp and all the other lamps function properly which makes this a bit more difficult than the typical brake light switch problem with the LR3. I have literally exhausted every possibility and thought I would give Just Answer a last minute long shot on a resolution. Please do not take my dissatisfaction with your answer to heart as I was hoping some Land Rover mechanic had a hail mary to solve my problem. Off to the dealership unfortunately!

Customer: replied 3 years ago.

Rating is simply based on the expert not having any new information for me to go on. This car is complex and this is by no means a reflection on this expert.

Customer: replied 3 years ago.
Relist: Other.
The answer provided was information I already had, and as such it does not help my current situation. I will most likely need to go to the dealer at this point for service.
Expert:  Chris (aka-Moose) replied 3 years ago.

Hello, I'm Chris. Thanks for visiting Just Answer.


Different tech here

With the key on the Green/Orange wire at stop lamp switch needs battery voltage. When the pedal is pressed, the Green/Purple wire will get voltage. At the Red wire on the stop lamp switch, there should be battery voltage only when the key is on. The Purple/Green wire will also have voltage, then lose it once the pedal is pressed.


The voltage must match battery voltage, the common issue is voltage drop from poor connections or wire issues. Also sun roof drain leaks effecting connectors in this area are common.

If all tests have so far passed then test the voltages at the ABS, Purple/Green and the Green/Purple wires need to be the same as battery voltage.

Chris (aka-Moose), Technician
Category: Car
Satisfied Customers: 43933
Experience: 16 years of experience
Chris (aka-Moose) and 7 other Car Specialists are ready to help you
Customer: replied 2 years ago.

Just as a followup, the car was taken to the Land Rover dealer to get this issue fixed. It turned out to be a bad ABS/Speed sensor on the right rear wheel.

Expert:  Chris (aka-Moose) replied 2 years ago.
Thanks for the update

Related Car Questions