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2002 Wagon Brake Light Problem

16K views 16 replies 6 participants last post by  Zedhead 
#1 ·
Greetings all,

Just this week I purchased a 2002 Outback Wagon and am now experiencing a problem with the Left Rear tail light on the hatch. More specifically, the issue is with the dual element bulb for the brakes. With the car's lights set to OFF for the daytime, only the dim portion of the bulb will illuminate when the brakes are pressed. Both elements, especially the bright, seem to illuminate on the right rear. When the vehicle's lights are turned ON the dim portion of the bulb lights up on both sides. When brake pressure is applied, the left read bulb turns completely OFF whereas both elements on the right light up. Basically the high intensity portion of the left never illuminates, and shuts completely off for the brakes at night.

I've already changed the bulb on the left side, but without any resolution to the problem. There is no obvious damage to the wiring in the immediate area. I would appreciate any insight on what I can troubleshoot next. I'm hardly car savvy, so this is my first real attempt at any any type of electrical troubleshooting on a car.

Thanks for any help you may be able to provide to the new guy.

Rob
 
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#2 ·
While we are waiting for someone who actually might know how to properly diagnose and fix the problem, an easy thing to try is to take some fine sandpaper and clean up the bulb socket. It may be a bad connection between the bulb and socket.

There are quite a few threads concerning where the wires run through the boot between the car body and the top of the hatch. Search the forum using the Google feature here for similar problems to yours.
 
#3 ·
This sounds exactly like a bad ground at the socket you're having trouble with.

If you have an ohmmeter, see if the socket ground is open or high resistance (it should be a small fraction of an Ohm at most). If it is, or you don't have the meter, see if you can find out how it's supposed to be grounded and check that.

[Edit to add] David's suggestion may solve the problem if it's just a dirty or corroded socket. It's the connection between the metal base of the bulb and the side of the socket that may be the problem.
 
#5 ·
The symptoms of having some filaments on when they shouldn't be, and off when they should, is often a broken filament in one of the dual filament bulbs that touching the other filament.

Another fault seen with the older bayonet style dual filament bulbs is flattening of the soft solder contacts at the base of the bulb enough so that the two contacts touch each other. This has a similar effect to the broken filament.

The third possibility that has been experienced in that generation is a conductive path between the two contacts in the wiring harness socket itself. Sometimes this is frayed wire in behind, but not uncommon is a trace of carbon (might look like corrosion) on the flat part of the socket. It can be the result of moisture that gets into the rear "finisher" (the red panel on the hatch), which is not uncommon.

That model has four, dual filament bulbs at the back for the clearance and stop lights. Any one of the bulbs or sockets will affect all of them.
 
#6 ·
A bad ground with a good dual-filament bulb will produce exactly the symptoms described. Since the OP already tried changing the bulb, a faulty bulb is unlikely.

I'm sure someone with an '02 service manual will come along with the information you need to run this problem to ground (see what I just did there?)

In the meantime, have you tried measuring resistance to ground in the socket to see if that's the problem, or at least cleaning the socket connector to the bulb base? If you don't have a meter and want to try some more diagnostics while waiting for someone with more information:

1) Remove the offending bulb. Lights off and step on the brakes. The "dim" filament in the right rear should not glow if it's the problem I suspect. Replace the offending bulb and it does.

2) Swap the bulbs between left and right sides. Does the problem remain in the same, or does it switch sides? If it stays the same, you know it's not the bulb, if it switches sides it is the bulb (this is unlikely since you already tried another).
 
#7 ·
I am not familiar with this exact problem on this exact model, but I do have some experience in troubleshooting electrical on various vehicles.

One of the things that I have found is that the brake voltage on one side will apply to both sets of lights in most vehicles.

Change BOTH bulbs.

Just helped a buddy with his brake lights on an older Honda Accord. It ended up just being a bad bulb on the starboard side. The higher current brake light filament had broken and shorted to the running light filament. It caused only half of the lights to go screwy, but that's probably due to the nature of electricity finding the least resistive path.

BTW, I diagnosed this by checking the voltage at the bulb, and noticed that it drooped to ~9V when he applied the brakes. This caused me to want to look at an alternate current sink. Popped open the other side and found the busted bulb.
 
#9 ·
Let me start off by saying I don't have a mutimeter or ohmmeter.

I've done the fillowing so far:

1. Sanded the contacts inside the socket with no rests the problem has remained.

2. I did some bulb swapping as well with some very odd results. The best case scenario is in daytime: the bright on the right and dim on the left come on with the brakes. With the vehicle lights on both tail lights will be on dim, but with the brakes depressed the right side will go bright and the left shuts off completed. There were some combos where pressing the brakes at night shut both lights off completely.
I'm wondering if I'm better off changing out the harness that goes to the brake lights and reverse lights on the left side, where I've been having the issue. Any other ideas?

Thanks for your help!
 
#10 ·
Those symptoms still smell of a bad ground on the left socket. Although "combos where pressing the brakes at night shut both lights off completely" doesn't quite fit, I'd still suspect that ground first, until eliminated. You can only swap bulbs of like type - just swapping at random won't necessarily give meaningful results.

Before changing the harness, find where the ground(s) in that harness is(are) and clean and tighten them. You're going to have to do that anyway. Grounds in cars are often black or mostly black (but no guarantees - you really need a wiring diagram for this).

If you can attach a test wire between a clean metal screw on the chassis and the bulb base while it's in the socket, see if the bulb works correctly when doing that. If that is the case, and you can identify the ground wire going to the socket, splice it and tie the end of the new wire to either the same ground point as the original, or a convenient screw in the chassis or, maybe, the liftgate. That will probably fix your problem.

Replacing the entire harness will be a PITA and expensive unless you can get a salvaged one (which may be no better). This should be a last resort and doesn't sound like it should be necessary.
 
#12 ·
It's a brand new car to you, and perhaps your first Subaru. When replacing all the tail/brake bulbs, make sure you're using the correct ones. The previous owner might not have. I believe the two-filament combination tail and brake lights are 1157.

Also, make sure that they are installed the right way. The offset pins are supposed to ensure this, but I've seen the bulbs forced into the socket the opposite way (180 degrees off).
 
#13 ·
Just got done sanity checking that in my manual.

I made another observation about my braking lights: even with my lights set to ON and brakes depressed, the red part of my tail light does illuminate at all. The turn signals work fine. Plan tomorrow is to replace all 1157's.

These lights should be function on both sides, correct?

I want to love this car so much, but the lights are driving me nuts!
 
#14 · (Edited)
These lights should be function on both sides, correct?
Yes, when the light switch is turned ON, there should be tail light bulbs on in the outer fenders (one each) and in the finisher (one toward the right, the other nearer the left side).
These are the lower intensity filaments.

When the brake is applied, the high intensity filaments of all four bulbs should also come on.

Plan tomorrow is to replace all 1157's.
When you do, remember to inspect the socket inside, especially the two contacts down at the bottom. Not much point replacing the bulbs if a socket is faulty. Make sure that the metal surround of the socket, that is, the part that the brass-colored metal base of the bulb contacts (where the two pins engage), is clean and free of corrosion -- that provides the ground for each filament.

I want to love this car so much, but the lights are driving me nuts!
It's over 12 years old, and there's going to be issues just from normal aging. Problems with the rear lights, especially those in the finisher are well known in these pages, and relatively-speaking, minor. You'll find quite a few threads/posts along with photos of faulty bulbs and sockets.

Here's a thread, same generation, with photos of a problematic bulb and socket.

http://www.subaruoutback.org/forums...t-fuse-blowing-water-draining-hatch-read.html

and another:

http://www.subaruoutback.org/forums...-don-t-work-won-t-shift-out-p.html#post420247 (see especially post # 13)
 
#16 ·
Re: harnesses. It has been my experience that electrical problems are rarely found in a harness. I would only look at replacing, or rewiring, a harness as an absolute last resort.

The majority, by far, of electrical problems lay in connectors and the units attached to them.

The places I would start first are;
1) Bulbs, right type and installed correctly (you wouldn't believe some of the stuff I have seen)
2) Corrosion. #2 cause of lighting failure after burned out bulbs. Clean the contacts.
3) Check that the wires are still connected all the way into their crimped on terminals that go into the removable connectors. Right where the terminal crimp meets the rest of the wire is the gotcha spot. This is where they normally break.

Most wire is stranded, except for transformer and house wiring. There are 7 32AWG wires in a 24AWG hook-up wire, for example. I have seen a number of crimp connections break a bunch of these after repeated insertions and removals of the connector.

You can usually diagnose a light problem without a multimeter and probably solve your issue by looking at these three common issues. But owning a decent multimeter is an important tool that will give you many years of fun and troubleshooting advantage.

Cheers!
http://www.subaruoutback.org/forums/11108-plain-om.html
 
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