WK2 Brake Lights not working (but third brake light does)

[Barom]

Hi Drover, thanks for that.
I will get at the globes tomorrow after work. The problem that I have is that the globes light up when the headlights are on - if it was a frayed wire, blown bulb or bad ground, wouldn't the bulb be dark at all times? What is getting me is that all the brake light bulbs in the rear end work fine with the headlights on but will not activate with the brakes (with or without the headlights on).

[drover]

Yep, they shouldn't come on with the headlights at all .....
So with headlights Off, ignition ON and foot on brake the 2 rear brake lights at the back are dark and only the back door light comes on but with the headlights on the led tail which runs around the edge comes ON and the brake light which is in the middle comes on (back door only has brake in the centre none with the tail lamp) does sound like a wiring cross over, I would be investigating the connectors and the earths as well, as by my diagrams the brake and tail lights don't have a connection , mind you I wouldn't be surprised if the WSM was wrong .....

Track the feed for the rear brake light to see where the connector which meets with the centre brake light is, testing for power , the only thing I can think of is a bent pin in a plug but if this has just happened it would be a long shot for sure..

I did notice the wiring diagram mention the wiring run is under/by the back door sills so have a look and see if any damage, not sure if it meant external or under the step plate inside the door frames... amazing what a bit of sand or water does..

One would think two globes lighting up on a LED circuit would throw a code because of power drain....

[LeCheese]

Originally Posted by drover

Yep, they shouldn't come on with the headlights at all .....
So with headlights Off, ignition ON and foot on brake the 2 rear brake lights at the back are dark and only the back door light comes on but with the headlights on the led tail which runs around the edge comes ON and the brake light which is in the middle comes on (back door only has brake in the centre none with the tail lamp) does sound like a wiring cross over, I would be investigating the connectors and the earths as well, as by my diagrams the brake and tail lights don't have a connection , mind you I wouldn't be surprised if the WSM was wrong .....

Track the feed for the rear brake light to see where the connector which meets with the centre brake light is, testing for power , the only thing I can think of is a bent pin in a plug but if this has just happened it would be a long shot for sure..

I did notice the wiring diagram mention the wiring run is under/by the back door sills so have a look and see if any damage, not sure if it meant external or under the step plate inside the door frames... amazing what a bit of sand or water does..

One would think two globes lighting up on a LED circuit would throw a code because of power drain....

Think you've got your own wires crossed a bit there mate - the 'LED strip' around the outside of both the outer (rear quarter) and inner (boot) light assemblies is actually just a single globe in each assembly that uses reflectors to give it the LED-looking outline.

You're right about the rest though of course - with lights on, both the outer and inner assemblies should have the 'outline', then when brake is depressed, brake lights should appear in the middle of the outer assembly.

I could be wrong, but I think the brake lights (in the outer assembly) are dual-filament bulbs, meaning that the parkers could still illuminate, but not the brake light, if the brake light filament has blown. A bit funny for both sides to go at the same time though, so might not be the issue...

[drover]

Originally Posted by LeCheese

Think you've got your own wires crossed a bit there mate - the 'LED strip' around the outside of both the outer (rear quarter) and inner (boot) light assemblies is actually just a single globe in each assembly that uses reflectors to give it the LED-looking outline.

You're right about the rest though of course - with lights on, both the outer and inner assemblies should have the 'outline', then when brake is depressed, brake lights should appear in the middle of the outer assembly.

I could be wrong, but I think the brake lights (in the outer assembly) are dual-filament bulbs, meaning that the parkers could still illuminate, but not the brake light, if the brake light filament has blown. A bit funny for both sides to go at the same time though, so might not be the issue...

I was going by the manual which says the tail lights are LEDs along with th centre door brake light and brake light is a globe, Mopar 3157KRD but it could be a filament or a led, have never looked but the wiring doesn't show it being a dual .... might have a lookie.... it is a strange situation for sure...

Update: had a lookie, the brake light is a wedge globe, it is twin element BUT only one set of wires, earth and the white/tan wire, tail is not accessable other than unplugging the lead (well on a 2015), reverse light is removable but mine didn't want to play so I left well enough alone................ easy enough to pull out once you have removed the plastic rivets, just gently wriggle and pull back the housing..

[FARWEST]

Mine is an earlier model but it has a dual filament globe for 'park' and brake...have replaced the passenger side globe...no brake light....nothing to do with what OP is chasing

[LeCheese]

Originally Posted by drover

I was going by the manual which says the tail lights are LEDs along with th centre door brake light and brake light is a globe, Mopar 3157KRD but it could be a filament or a led, have never looked but the wiring doesn't show it being a dual .... might have a lookie.... it is a strange situation for sure...

Update: had a lookie, the brake light is a wedge globe, it is twin element BUT only one set of wires, earth and the white/tan wire, tail is not accessable other than unplugging the lead (well on a 2015), reverse light is removable but mine didn't want to play so I left well enough alone................ easy enough to pull out once you have removed the plastic rivets, just gently wriggle and pull back the housing..

Yeah weird about the manual - the top third brake light are LEDs, but the light clusters (incl. reverse and indicators) are all halogen. I believe the exception to this is possibly the SRT lights, which may be LED.

[LeCheese]

Originally Posted by FARWEST

Mine is an earlier model but it has a dual filament globe for 'park' and brake...have replaced the passenger side globe...no brake light....nothing to do with what OP is chasing

OP says that the brake lights illuminate when headlights/parkers are on, but don't become 'brighter' when brake is depressed - if that's the case, it could be the brake filaments have blown. Or have I misunderstood?

I know OP mentioned bench testing, but again, if dual filaments not sure you'd be able to replicate the voltage signal differential for parkers/brake appropriately.

Edit: just re-read and OP has already tried new globes. Should probably disregard this then!