2004 XC70 brake lights wont come on after changing bulbs

[everythingsbroken]

hello, i recently replaced my brake light and reverse light bulbs on my xc70. After switching out the bulbs my brake lights wont come on at all. the third high light still works fine and the reverse lights come on as well. its just the low 2 brake lights. I've done some research on here and other forums but I've had no luck with finding the problem.

here's what I've tried:
replacing the brake relay
checking / replacing literally every fuse i can find related to brake lights
swapping the shunts with different shunts, work fine in another socket
switching the bulbs with the reverse light bulbs. all the bulbs work
and simple reinstalling the shunt in case it was in wrong

no luck so far, id like to have functioning brake lights though

[jonesg]

Have you tried a test light to see if theres volltage at the sockets.
Getting those bolb holders back in place properly is a bitch.
I removed everything so I coud get at them with both hands.
That required pulllig a bunch of trim from above the door and side window trim.
torx 25 driver, 10mm deep socket on wobble drive, magnet pickup tool etc, its a pain but that was the only way I could get it in my hands.

When I changed the other side I marked the bulb holder with a sharpie before removing it.

[volvolugnut]

Access is bad for these bulbs (Assume same as 2001 V70). Try to remove and reinstall the brake bulbs. While the bulbs are out, check voltage at the sockets and confirm the bulbs are good.
volvolugnut

[scot850]

These connectors can actually melt or fail. I have one bulb holder that for some reason will not work. I cleaned it and checked the bulb and it was fine. I had spare connectors from another light unit and swapped it in.

The contact point for the bulb holder can melt through. Hard to see without removing the light unit.

To get full access is a pain, but the only real issue is the plastic U-clips that break when you have to remove the lower trim around the tailgate opening.

Otherwise it is fairly quick to access and remove the light units, but then I have done this many times pulling spare units from the junkyards for others.

Neil.

[everythingsbroken]

Access is bad for these bulbs (Assume same as 2001 V70). Try to remove and reinstall the brake bulbs. While the bulbs are out, check voltage at the sockets and confirm the bulbs are good.
volvolugnut

I'll give the test light a shot, I'm fairly certain I'm getting power back there though. Reinstalling the brake bulbs / shunts hasn't made a difference

[everythingsbroken]

These connectors can actually melt or fail. I have one bulb holder that for some reason will not work. I cleaned it and checked the bulb and it was fine. I had spare connectors from another light unit and swapped it in.

The contact point for the bulb holder can melt through. Hard to see without removing the light unit.

To get full access is a pain, but the only real issue is the plastic U-clips that break when you have to remove the lower trim around the tailgate opening.

Otherwise it is fairly quick to access and remove the light units, but then I have done this many times pulling spare units from the junkyards for others.

Neil.

I've pulled it all apart before to replace the gas piston springs in the tailgate, but I think you're right and I'll have to get back in there to see what's up with the connectors. I didn't know they could melt through. One worked beforehand and one was burnt out. But I'll try swapping the shunts around.

[firstv70volvo]

These connectors can actually melt or fail. I have one bulb holder that for some reason will not work. I cleaned it and checked the bulb and it was fine. I had spare connectors from another light unit and swapped it in.

The contact point for the bulb holder can melt through. Hard to see without removing the light unit.

To get full access is a pain, but the only real issue is the plastic U-clips that break when you have to remove the lower trim around the tailgate opening.

Otherwise it is fairly quick to access and remove the light units, but then I have done this many times pulling spare units from the junkyards for others.

Neil.

I've pulled it all apart before to replace the gas piston springs in the tailgate, but I think you're right and I'll have to get back in there to see what's up with the connectors. I didn't know they could melt through. One worked beforehand and one was burnt out. But I'll try swapping the shunts around.

The plastic in this rear upper light assembly is in good shape and you can see the metal contact plate and the bulb contact rub area when the light is twisted in place. The plastic holds the metal contact plate in place but what happens is the plastic melts and or breaks from the bulb heat then the metal plate pushes outwards and a poor contact is the result, intermittent light or no light at all. Check the condition of the plastic carefully and push on the metal contact plate or watch it as you twist in the bulb in to see if moves outward from the plastic being damaged.

[volvolugnut]

The bulb holder design is not what I would call robust. Bulb holders going back to 240 series were not robust.
volvolugnut

[vtl]

Did you check the brake pedal switch? It may pop out of the bracket. Or its travel may need to be reset. There's a sleeve on it that you simply pull out to the maximum length, then press the pedal and it self-adjusts.

[everythingsbroken]

Did you check the brake pedal switch? It may pop out of the bracket. Or its travel may need to be reset. There's a sleeve on it that you simply pull out to the maximum length, then press the pedal and it self-adjusts.

I can hear a clicking when I press the pedal like the switch is actuating, but I'll try that