Turn Signal and Brake Light Problem (Resolved!) SEE PIC

[Lance Allison]

There are some related posts on this problem, but they are unique to A4 cars, namely A4 turn signal/hazard switch relays, so I'm thinking I may have a different problem since I have an A3 Jetta.

I needed a new right rear brake light bulb, so I bought 2 from the dealer and replaced both sides.

Now here comes the problem...right now a few things are happening at different times.

1. Brake lights and turns work as designed (happens about 75% of the time) OR...

2. Turn signals do not flash at all, both directional indicators on the dash come on dimly when the brake is pressed, and the brake lights do not work. Sometimes this varies and the turn signals and brake lights come on very dimly. (About 15% of the time) OR...

3. Brake lights work normally, but the turn signals flash very quickly. (remaining 10% of the time).

I cleaned all 4 sockets and tried new bulbs in the brake lights and in the front turns. Also, if situation 2 or 3 happens, if I remove and reinstall the rear brake light bulbs, the problem appears to be resolved for awhile...sometimes days.

Any ideas?

[ February 14, 2003, 22:32: Message edited by: Lance Allison ]

 

[RIP TDI]

When the 2 brake lamps don't light, how about the CHMSL (center brake lamp)? The rear brake/turn/tail lamps have a common ground within each side assembly. The right side then runs one wire from that point to the left side assembly's common ground point and then actually grounds both sides to the body with one wire. The CHMSL has its own separate ground wire. If the CHMSL lights consistently, the problem may be with either the b/t/l main body ground or the internal ground(s) within the side unit(s).

If the CHMSL behaves the same as the side brake lights, the problem would seem to be further upstream.

 

[Lance Allison]

The center brake light does not work when this problem is occurring. It does work properly when the brake lights/turns are working.

 

[bowlerman]

check all fuses? maybe a relay is going?

 

[Nutsnbolts]

I am thinking you've lost the ground for the rear lights. You might want to check your reverse lights when you're having the problem- I would bet those don't work at the same time, and might even turn on the directional indicators in the dash.

The reason is that once the ground in the rear is lost, then the only place those lights can ground is back up through the directional indicators in the dash, as well as the indicators in the front bumper. While they may not be receiving power, they are still always grounded, and always in parallel with the blinkers.

If it turns out that this is not the problem, then while the brake lights are acting funny, try wiggling your directional switch while you have your foot on the brake and see if you can make the problem come and go. This would indicate a bad directional switch, which I have seen some problems with in the past in the A3s. Let us know what you find!!!

-Rich

 

[Lance Allison]

I don't believe the rear backup lights work either when this takes place.

I had the problem last night. I locked the brake pedal down and started messing around back there. To make it work, I ended up unplugging the harness leading from the outer right rear light assembly that piggybacks into the outer left assembly. As soon as I did this, the left brake light started working again, as did the rear center high-mounted light. I then plugged the harness back in. I'm not convinced this fixed the problem since it seems to come and go anyway, but we'll see.

Where is the ground for the lights?

On another note, my directional switch could be at fault as well. For about 2 yrs, my cruise will switch off sometimes when using the lever to activate the signal when changing lanes. About 1 in 10 times, if I move the lever, the cruise will turn off. Hmm///

[ February 06, 2003, 12:09: Message edited by: Lance Allison ]

 

[Lance Allison]

Okay, I found the problem this weekend. After examining all 4 bulb holders, the rear outer holder had what appears to be a hot spot around the 2nd pin (brown/ground). It wasn't terrible, but enough damage was done to cause grounding problems with the lights. I tried to clean the contacts, but it didn't help.

The dealer, of course, had to order the part, so for the time being, I swapped the left and right side bulb holders. 4 days and counting...no problems at all.

I'll post a pic a bit later.

 

[Lance Allison]

Here are pics of the bulb holder. The strip across the top should be all together. Notice how pin #2 has a melted section...Any thoughts?

The only thing I can think of is the last time I replaced brake light bulbs, the dealer gave me regular 1156/1157 bulbs instead of the proper P21Ws...

[ February 14, 2003, 22:35: Message edited by: Lance Allison ]

 

[MOGolf]

Which type of bulb was it? 1156 = single filament, 1157 = double filament. The 1156 would be OK, but the 1157 might have made for the excessive current draw.