Tail Lamp Inoperative- Bad Ground?

[ChiefRider]

My lower left rear lamp has stopped functioning. The bulb is fine, so I am guessing the problem may be a bad ground, but where to begin searching? Has anyone else had the same specific issue, or a good place to begin looking?

Thanks!

[80stech]

These are infamous for problems with the bulb holder contacts and there is a lot of info about a couple of methods on how to repair posted here.

[ajgregory3tr]

Originally Posted by ChiefRider

My lower left rear lamp has stopped functioning. The bulb is fine, so I am guessing the problem may be a bad ground, but where to begin searching? Has anyone else had the same specific issue, or a good place to begin looking?



Thanks!

I have the same ongoing problem and have found it it to be a bad connection between bulb and pcb. I renewed the bulb holders which sorted one of the bulbs, but still have intermittent problem with the other side. On an earlier 320 of the same era I found the earth to light unit failure to be the source of the problem.

Sent from my SM-S921B using Tapatalk

[80stech]

There are a couple of different ways to go about the repair but I used the solder method, putting on a bit of acid core solder on to the contact strips has been a permanent fix for probably 10 years!

[andrewwynn]

That's a lot quicker than my fix. As long as the contact is good after so it stops generating heat from high resistance it should be a permanent fix.

I restored the spring contacts to factory position by adding metal screws and bending the ends to reset the height of the contact.

The solder method likely is a lower resistance contact since the factory solution is zinc plated steel which is a terrible conductor.

If i had to do again I'd do both, but it doesn't need to be back to factory. The solder bump puts the contact where the lamp expects it with a lot less work.

[wpoll]

I've found solder on BOTH the steel/zinc plate and the small contact tabs on the bulb holders works best (longest!).

[haigha]

Last fall, after 21 years without issues, I used Andrew's fix when the running light wasn't working on one side (the brake light would still come on). But, I noticed both sides were humming loudly. It seemed like it was going to be an ongoing battle.

After inspection, I changed out the whole set of four for about $120 on Amazon. The third party set uses standard sockets. Plus I got lightly smoked ones which look more modern to me.

[wpoll]

Originally Posted by haigha

... I changed out the whole set of four for about $120 on Amazon. The third party set uses standard sockets. Plus I got lightly smoked ones which look more modern to me.

I have yet to see a set of aftermarket tail lights that are correctly configured (wired) for the LCI cars (and I have looked...). They may exist, but I have yet to see any...

Be aware that the LCI tail lights are wired differently from pre-facelifts tail lights and use different bulbs etc.

[haigha]

Originally Posted by wpoll

I have yet to see a set of aftermarket tail lights that are correctly configured (wired) for the LCI cars (and I have looked...). They may exist, but I have yet to see any...

Be aware that the LCI tail lights are wired differently from pre-facelifts tail lights and use different bulbs etc.

These are the ones I bought, Wayne:

https://www.amazon.com/gp/product/B07N8G4SQN

They are wired correctly for my 04 4.4i. They even included wiring and sockets for the rear fogs (though I don't have them so can't say that the wiring works for them in particular).

One of the plugs was difficult to insert... I had to bend the pins inside the connector.

[wpoll]

Originally Posted by haigha

These are the ones I bought, Wayne:

https://www.amazon.com/gp/product/B07N8G4SQN

They are wired correctly for my 04 4.4i. They even included wiring and sockets for the rear fogs (though I don't have them so can't say that the wiring works for them in particular).

One of the plugs was difficult to insert... I had to bend the pins inside the connector.

Good to hear they work but the giveaway here is they are listed to work with cards from 2000-2006, which indicates a lack of consideration for the lighting changes introduced in Sept. 2003 with the LCI update.

How many of the rear red sections are lit up when the lights or on (not braking)? All four or just two? LCI cars use all four rear sections as low-intensity tail lights, the lower two red sections as high-intensity brake lights (normal braking) and all four red sections as high-intensity brake lights (rapid brake application/ABS activated etc.)

I wonder if this force-dependent braking feature works with these? Hard to check/test!

The best feature of these aftermarket tails is they do away with the poor steel/zinc lamp circuit connections!