How do I replace a brake light on the Avant model - I cannot see how to get into the light cluster.

I have the similar problem with my 2000 model. On mine I have narrowed it down to the rear light cluster on the right as you look at it from the rear (drivers side in the UK). Here's how I fix mine, although it does keep happening every now and again:
Remove the lights cover from inside the boot, it is held in place by a couple of plastic nuts.
Remove the strip of lights that are clipped into place.
There is an electrical connector block attached to the now removed light cluster. Undo this and the whole set of lights will be free.
Where the connector block fits to the light cluster clean all of the terminals. I use one of my wifes nail emery boards.
Make sure the female connectors on the connector block are all fairly snug so when put back together it is a tight fit.
Clean with electrical contact cleaner if you have any (not really necessary but I had some anyway).
Reconnect the block and test your lights, put back together.
I suspect it is an earth fault but I ran a separate earth to the unit but it didn't improve.
Other faults I noticed is the rear wiper operates when the front one only is on and I touch the brakes. Also when I lock the car when the indicators flash to show it is locked the rear high level brake lights flash as well. I was thinking of trying another light cluster, but 25 pounds from a breakers yard seems a little steep for a minor irritation.

the third light works off the light cluster main wire at the rear so if there is power to the this light then there is a problem with the cluster link. check with a meter at the connector with the brake applied if power. then clean the plug to the cluster.

Hi, I have a couple of questions.
1. were the signals working before you replaced the brake light bulbs, and did you use the recommended bulbs?
2. Do the brake lights work now?

The brakes and signals use the same filaments, so these things are tied together.

The lights get power from somewhere else, not their control button - you will need to access the wire connector at the left cluster and locate the wire that delivers the power and the status of the grounding connection/bolt (most likely it's corroded). Since the cluster of lights above the rear window are the central brake lights only it means that if you get them constantly on then the brake lights are constantly on . To check for that is easy, just test the brake pedal switch.

I assume you have replaced the lamps/globes with new ones, if not this is the first thing to try.
If your car is fitted with a "faulty light" sensor, ( i.e. if a warning light on the dashboard comes on when you apply the brake and a brake light bulb is not working), this may be the problem. Follow the wiring for the rear lights from the light clusters inside the trunk and you may find the wiring harness plugged into an encapsulated unit in the rear somewhere. Test if power is coming out of this unit when brakes are applied. Or, remove the covers on the brake light clusters from inside the car and check the wiring to the rear window brake light. Very often this is connected to the same ground as the drivers side light. However, the parking and tail and reversing lights usually work off the same ground, so this seems unlikely.

Here are some things to check:-

1 The brake light switch
2 The fuse for the brake lights
3 The bulbs for the brake lights
4 The bulb contacts in the brake lights
5 The earth connections in the rear light clusters
6 Generally check for loose or broken wires in the vucinity of the brake light switch and the rear light clusters.

SOUND LIKE YOU HAVE FAULTY BRAKE LIGHT SWITCH.

Hi

In the trunk, just un clip the light cluster, twist out the bulb, and renew the stop bulb, refit the light cluster.

Good Luck !

John.

A FixYa rating would be appreciated please !

Brake light switch, located on upper brake pedal should be checked, that is most likely your brake light issue, but U say tail lights aren't working, but running lights do, tail lights and running lights I would consider to be the same, so can u clarify that for me? Let me know how the u do w/ brake light switch, and if u have issue w/ tail lights?