[Jagster]

When my lights are on my brake lights are illuminated like the brakes are being applied. Also it seems like I change the bulbs often because they burn out quickly. Only rear light the seems to be working correctly is the rear deck brakelight.

Any idea what is wrong?

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[mrboca]

Can you clarify a bit ? Do you mean that the brake lights at both sides are turned on when you turn the head / tail lights ON from the headlamp switch, and the brake pedal is not depressed ?

Don't you have any lamp defect error warning when you turn the headlamps on then ?

Are you sure you are using the correct brake/tail light bulb ?

 

[Jagster]

Can you clarify a bit ? Do you mean that the brake lights at both sides are turned on when you turn the head / tail lights ON from the headlamp switch, and the brake pedal is not depressed ?

Don't you have any lamp defect error warning when you turn the headlamps on then ?

Are you sure you are using the correct brake/tail light bulb ?

Yes to clarify, the rear brake lights on both sides are illuminated brightly (like the brake pedal is being pressed) when lights are on and brakes pedal is not pressed. Lights are turned on with headlamp switch. Im using the size bulb stated in the manual.



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[mrboca]

And you have no lamp defective warning display ?

If the problem is on both sides, the common point is the illumination control module (the module behind the headlight knob). It appears that there is a short between the two bulb drivers.

What happens when you press the brake pedal with the tail lights turned OFF ? Do brake lights (apart from the central one) turn on? If they do, do the tail lights in the same combo bulb turn on as well ?

 

[Jagster]

And you have no lamp defective warning display ?

If the problem is on both sides, the common point is the illumination control module (the module behind the headlight knob). It appears that there is a short between the two bulb drivers.

What happens when you press the brake pedal with the tail lights turned OFF ? Do brake lights (apart from the central one) turn on? If they do, do the tail lights in the same combo bulb turn on as well ?

Yes the defective lamp warning is there but we change the bulbs and it goes away but returns because the bulbs burn out within a short time (couple weeks if that)

Pressimg the brake pedal with the tailights off illuminate the brake lights but not to the brightness of what they should be (when the bulbs are not burnt out). I dont know if this makes sense.

Right now Im driving it with the brake lights not working (except center light). What Ive been doing sometimes is turning my lights on when I brake to replicate brake lights. I only work 10 min away.


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[mrboca]

OK, curious problem

So if pressing brake pedal is "brake on", and switching the tail lights is "tail on":

brake on + tail on = light on
brake off + tail on = light on
brake on + tail off = light on
brake off + tail off = light off

Do the bulbs burn at the same time ?
Do you know which filament burns (the brake or the tail, which is thinner) ?
And always the same filament for each bulb?
When one bulb burns out does the other one at the other side go off too ?

How did this problem come up ? After some maintenance work / repair ?

 

[SkippyJasper]

Just for discussion, what is the voltage when the engine is on?
Sounds like it might be high.
Skippy

 

[Jagster]

OK, curious problem

So if pressing brake pedal is "brake on", and switching the tail lights is "tail on":

brake on + tail on = light on
brake off + tail on = light on
brake on + tail off = light on
brake off + tail off = light off

Do the bulbs burn at the same time ?
Do you know which filament burns (the brake or the tail, which is thinner) ?
And always the same filament for each bulb?
When one bulb burns out does the other one at the other side go off too ?

How did this problem come up ? After some maintenance work / repair ?

Right now....when I press the brake, no lights come on (I believe the brake light bulbs are burnt out again on both sides). When I turn the tail lights on, the tail lights illuminate very bright just like the brake lights are being applied (without pressing the brake pedal). When the brake light bulbs were working, during the day when the tail lights were off, when applying the brake the lights would light up but not super bright like they should but more like the brightness of just tail lights being on.

I don't know if that make sense. But we've had to replace the brake light bulbs every couple weeks it seems like.

 

[mrboca]

Almost sounds like the lines for the tail light and brake light (of the same light bulb) are crossed. In that case the tail light switch would power the brake light filament and the brake switch would turn the tail light on. So if you tail light filament is gone, the pressing brake pedal will not light the tail light up. But if crossed, you would have a lamp defect warning I thought.

It could also be a short between the circuit 54 ( tail light) and circuit 58 (brake light) somewhere along the wiring or internal to the illumination module.

I would take the stop light bulbs out and measure resistance between the two circuits at the metal receptacle on one side, then the other (with key out). You should not see a short.

Did you do any electrical work on the car prior to this ?

 

[Jagster]

Almost sounds like the lines for the tail light and brake light (of the same light bulb) are crossed. In that case the tail light switch would power the brake light filament and the brake switch would turn the tail light on. So if you tail light filament is gone, the pressing brake pedal will not light the tail light up. But if crossed, you would have a lamp defect warning I thought.

It could also be a short between the circuit 54 ( tail light) and circuit 58 (brake light) somewhere along the wiring or internal to the illumination module.

I would take the stop light bulbs out and measure resistance between the two circuits at the metal receptacle on one side, then the other (with key out). You should not see a short.

Did you do any electrical work on the car prior to this ?

No electrical work done at all. It just started doing this. I figured it may be an electrical/wiring issue due to the age.

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