My Land Rover Discovery's brake lights aren't working. The bulbs are fine, as is the fuse. All other lights working. Where could the problem lie? Is it maybe connected to the electrics on the tow-bar?

Unlikely to be a fuse blown. Doesn't your Discovery have Daytime Running Lights? If so the right side might be a blown fuse. If the rear lights are on, that mean you have the nighttime lights on.

My mother worked at Land Rover in Solihull for 12 years. :>)

Fuses and relay Land Rover Discovery 2 - Fuse box diagram

fusesdiagram.com https://fusesdiagram.com > land-rover > fuses-and-rela...

Passenger compartment fuse box is located below an to the side of the steering column. Remove cover using a coin or small screwdriver and turning 90 degrees.

They seem to suffer with funky electrics

https://www.google.com/search?q=land+rover+discovery+2+left+front+left+rear+lights+on+all+the+time

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The brake light switch is on top of brake pedal arm. Check your bulbs, and connections to the rear lights (unplug harnesses and clean the connectors as well as bulb(s) etc... )

Also, it (shouldn't) be the brake light switch if you can shift out of park. Good luck.

Check that your fuses and bulbs are still fine

1. Pull out side facing seat or pocket cover.
2. Unscrew fastener and remove access panel.
3. Turn bulb holder anti-clockwise to release.
4. Remove bulb.
Refitting is reverse of the above procedure

Hi it sounds like a wiring short taking out multiple circuits check all fuses and recheck that you haven't melted the new part again it's unusual for these to melt unless they are being shorted out

does the switch have power to it ??

First check that the brake lamps work, if they do not , check the fuses , the switch and wires to it at the brake pedal. The transmission shift lock is controlled by a brake switch. Hope that helps

If the high level brake lamp works and the other 2 lamps have good bulbs, then there is a power loss, most propably with the installation. You should go to an auto electrician to see where the break is.
If someone has recently done any work on the electrics, you should recheck. It is not a seperate fusable power supply system or brake switch for the high level brake lamp, it will take its power from the fused system that the other 2 have.
Hope this helps

Check the circuit board that the bulb plugs into and make sure it is not burned or that the contacts are not damaged.

If your brake lights don't work Its because you blew the fuse  which Is located In the main fuse panel under steering wheel.  Without break lights your rover will fire up nice but wont shift out of park until you replace the fuse.  If your ABS Is acting up It Is also an easy fix.  Disconnect the ABS from each wheel.  You still got all wheel disc breaks that work great but no ABS.  Your other option is  thousands of $$.  If your breaks are weak check your master cylinder and make sure you got enough fluid and that you are not loosing the fluid.  If you notice you are leaking brake fluid because you have to keep filling it up but cannot find a leak anywhere.  I bet I know where It is.  Check your rear break lines and make sure one of them didn't get caught in your rear springs and pinched ever so slightly when you were doing dounuts In the snow.
Good luck,