[Cloud9...68]

I had always been proud of the fact that my 3rd brake light assembly had always worked perfectly - nary a burned out bulb, ever. Well, as I was testing it today, wouldn't you know it, the entire assembly is dead. I figure this must be easier to troubleshoot than if it were a few bulbs (and cheaper, too, as I understand the bulbs are quite pricey...). I checked all the fuses in the fuse box in the engine compartment, and all is well. I did a search as usual, but not much came up. Any suggestions as to where to start? I took the brake light assembly out, and didn't see anything obviously wrong, other than that the connectors (at least I assume that's what they are) when the assembly screws into the hatch had a lot of surface rust. I sanded them with some light sandpaper, but that didn't help. Thanks.

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[DaveN]

First hings, get a meter and have someone step on the brake; is there 12V at the rear connections? If so start looking forward. The other thing, everyone jump in to correct me, but isn't the brake light part of other electrical systems such as the alarm? I seem to recall that is the rear 3rd light doesn't work something else is impacted.

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[jg968]

You'll need to take the light assembly apart and clean the internal contact areas too. While you're in there you might be tempted to do a bulb replacement to all LEDs. Pretty easy to do.



Jerry

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[Cloud9...68]

Thanks for the responses.



DaveN - The assembly is held in place by a couple of holders (not sure what else to call them...) which I'm guessing serve as the electrical connectors as well, as I don't see any other connectors. When I place a voltmeter across the connectors after removing the brake light assembly, and press the brake using a long stick, the regular brake lights come on, but there's no voltage between these two connectors.



As far as the assembly itself, its behavior is kind of flaky. When I take it apart and connect it to the car battery, five of the seven bulbs light up. I just happen to have several spare bulbs, so I installed them in place of the two that weren't working, and only one of them lit up. I wiggled the one int he bad position, but it didn't help. I then swapped one of the older, working bulbs, with the one that wouldn't light up, and even with the new bulb, the bad position still didn't light up. Then I wiggled the bulb in its connector some more, and was finally able to get it to light. So my guess is none of the bulbs were bad in the first place; I just have some flaky (or "dodgey" as the Brits like to say) connectors. However, even after I was able to get them all to light, the assembly still won;t light up when I pout everything back. So it seems, as is so often the case with me, that I have multiple problems <img src="/forum/images/smilies/968/sad.gif" class="smilie" alt="" /> .



I've heard several people say replacing the bulbs with LEDs is a good idea. Are these a straight drop-in, or do I need a whole new assembly? What type/size LEDs would I need (I don't know much about LEDs)? Do I need to wire a resistor in series with them? Basically, could someone please provide a step-by-step procedure as to how to convert to LEDs? However, bear in mind that I'm selling the car, so I don't want to get into any expensive upgrades at this time. My goal is to get the assembly back into proper working condition, not to improve upon it, unless as improvement will help solve the problem. But I think the root cause of my problem is that I'm not getting any voltage to the assembly. Or, as DaveN says, maybe there's a problem with a related system. Last time I checked, the door LEDs were flashing when I lock the car, indicating the alarm is working. In fact, I've set it off a few time recently during various electrical troubleshooting exercises.



Thanks again.

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[DaveN]

On my car the connection is a black flat ribbon connector that screws to the car. If there is no voltage there then it's back to the fuse box. One assumes that the 3rd brake light is not related to the postion of the ignition switch? I have never stood behind my car to see what operates with and without the ignition on.

While LED conversion is easy and not very expensive I would resolder all the existing connections first if you are selling your car. I am sure there is a DIY here and yes you do need a limit resistor. There are some special 12V LEDS that have them in situ but the price is more.

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[Cloud9...68]

[quote name='DaveN' timestamp='1295821161' post='103982']

On my car the connection is a black flat ribbon connector that screws to the car. If there is no voltage there then it's back to the fuse box. One assumes that the 3rd brake light is not related to the postion of the ignition switch? I have never stood behind my car to see what operates with and without the ignition on.

While LED conversion is easy and not very expensive I would resolder all the existing connections first if you are selling your car. I am sure there is a DIY here and yes you do need a limit resistor. There are some special 12V LEDS that have them in situ but the price is more.

[/quote]

Black flat ribbon connector, eh? Hmmm, I don't see anything that meets that description on my car. In the picture below (sorry about the blurriness - I was drying to hold the shop light with one hand, the hatch in position with my other hand, and take the picture with my third hand - good help is hard to find...), you can see two tabs, which are near the visible mounting screws. My 3rd brake light assembly slips onto these tabs, and is then held in place by a pair of screws. I'm assuming it's these tabs that carry the current to the assembly, because when I apply 12 volts to the assembly at the location where the assembly meets the tabs, it (at least mostly) lights up. But when I press on the brake pedal, there's no voltage signal across these tabs. Does this make sense?



As far as the required ignition switch position to activate the brake lights, on my car, it has to be in the full clockwise (accessory?) position - the one right before the "start the car" position.

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[flash]

sounds like a break in the line that feeds the hot one of those tabs

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[Tomikaze]

I'm troubling shooting the exact same problem as we speak. Did you ever figure it out?

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[Cloud9...68]

Nope. Kinda like the sunroof - still a total mystery. But I'm converting it to a mostly-track car, and am in the process of reassembling the engine, so I haven't gone back to look at the 3rd brake light. One of these days...

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[Tomikaze]

Gonna drive me nuts until I fix it. Appreciate any input anyone can give here. I'm not an electrician so this isn't my strong point. No power to the exact same part Cloud9..68 posted above. Pulled the fuse and it's fine but checked it at the fuse with a voltmeter and there is no power there either. Power at all the other fuses. Anyone have experience with the wiring and were it goes? Help!

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