Stop lamp issue..... Fix?
#31
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#32
Electron Wrangler
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It should happen every time on start-up until the first time you activate the bulbs (e.g. step on the brake pedal). If you start with your foot on the brake you may never see it... Its more obvious of an issues with a manual car...
The bulb monitor cannot test the status of the stop lamp bulbs until they are activated - so the warning stays on until then. I think Porsche intended you to tap the brakes initially after start-up to complete the test before you move away...
Alan
The bulb monitor cannot test the status of the stop lamp bulbs until they are activated - so the warning stays on until then. I think Porsche intended you to tap the brakes initially after start-up to complete the test before you move away...
Alan
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#34
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alright, so i found a diff bulb control unit and replaced it. now when i hit the brake pedal, it goes out........ sort of. it just gets real dim... thoughts?
#36
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well when i first start up the car, nice and bright STOP LAMP. then when i hit the brake, to turn it off, it just gets alot dimmer. but does not go out.
#38
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Bad ground causing current leak to the light? That has been my experience with things that are supposed to go out but are still on dimly.
Dan
'91 928GT S/C
475hp/460lb.ft
Dan
'91 928GT S/C
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#39
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clean the ground point in the right side of the hatch floor behind the rear side of the quarter panel liner
#40
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interesting that the light switch has anything to do with brake lights, as was reported by someone.
Anyway, I have a ground removed on the passenger side and when the signals go, the middle light and then the turnsignal light go back and forth illuminated, albiet dim. when the ground connected, all is well.
I have NO brake lights now, and trying to track it down starting tonight. I seemed to remember a connector at the top of the brake pedal axis, so that when it was not connected, brakes lights didnt work. is that true, or is it controlled at the master cylinder?
Getting back to the original question, its odd that the brake lights are in the "On" position . the brake switch basically runs a connection of two pins on the bulb controller. (pin 12 to 14). with that connection made, the bulb controller pin 4 gives power to the brake lights which end up at a ground . the other side brake light gets power and ground from bulb controller terminal 13 to 1. So, in order for the brake lights to be on ,I would think the bulb controller is mainly responsible. Im also looking at the 88 wsm, which has the hood light, which interestingly, only has one side going through the hatch mounted brake light to ground. if that bulb is bad, does only one side of the brake lights work? there might be a shared ground, so that doesnt happen. the wiring diagrams are a little hard to follow.
Anyway, I have a ground removed on the passenger side and when the signals go, the middle light and then the turnsignal light go back and forth illuminated, albiet dim. when the ground connected, all is well.
I have NO brake lights now, and trying to track it down starting tonight. I seemed to remember a connector at the top of the brake pedal axis, so that when it was not connected, brakes lights didnt work. is that true, or is it controlled at the master cylinder?
Getting back to the original question, its odd that the brake lights are in the "On" position . the brake switch basically runs a connection of two pins on the bulb controller. (pin 12 to 14). with that connection made, the bulb controller pin 4 gives power to the brake lights which end up at a ground . the other side brake light gets power and ground from bulb controller terminal 13 to 1. So, in order for the brake lights to be on ,I would think the bulb controller is mainly responsible. Im also looking at the 88 wsm, which has the hood light, which interestingly, only has one side going through the hatch mounted brake light to ground. if that bulb is bad, does only one side of the brake lights work? there might be a shared ground, so that doesnt happen. the wiring diagrams are a little hard to follow.
#41
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OK so here is what i found out today. i took my old control unit and heated up the solder spots for the connectors (just for giggles), and re tried it. does not work. i even tried a new central control box (dead pedal) and same thing, but it also made my coolant light and engine oil light dim as well.
here is a picture of the STOP LAMP light before i hit the brakes.
![](http://i575.photobucket.com/albums/ss197/Ducman82/928/002-2.jpg)
and here is a picture after i hit the brakes (dim stoplamp light)
![](http://i575.photobucket.com/albums/ss197/Ducman82/928/001-3.jpg)
i cleaned the contacts in the bulb control, the CW control, and even ground down the ground on the right rear, and above the fuse block. i did change the lights to LED, but that should not matter. work fine. power, no power etc.
here is a picture of the STOP LAMP light before i hit the brakes.
![](http://i575.photobucket.com/albums/ss197/Ducman82/928/002-2.jpg)
and here is a picture after i hit the brakes (dim stoplamp light)
![](http://i575.photobucket.com/albums/ss197/Ducman82/928/001-3.jpg)
i cleaned the contacts in the bulb control, the CW control, and even ground down the ground on the right rear, and above the fuse block. i did change the lights to LED, but that should not matter. work fine. power, no power etc.
#42
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Oh - now you tell us...what did you change for LED's and why do you think that won't matter??
Put the incandescents back and see what happends - I bet that will fix it...
Alan
Put the incandescents back and see what happends - I bet that will fix it...
Alan
#43
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they work perfect wit the rest of the dash. why would just the stop lights change it? ill try it tomorrow i guess and swap it out. be like the 5th time iv taken that pod out. i am getting good at it
#44
Team Owner
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wait your sending us on a wild goose chase without all of the pieces to the puzzle.
Remember the more info you provide the better the guess can be to solve your problem
Remember the more info you provide the better the guess can be to solve your problem
#45
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what i also forgot to state, was it was doing this BEFORE i went LED. My bad, i suck. if the control unit powers the bulbs, what pin on the controller tells the Warning system to turn on the light? maybe it is pinched or grounding out or something. thats one reason i did the change over, check out the dash, wire, bulbs etc. rule them out. still have the problem.