Save Money on Tail Light Repair Cost with this Simple DIY Guide

Modern cars are fairly complicated when you break them down to their individual system. No matter how hard car makers try to build perfect machines, they rarely come close. Even the crowd favorites such as the BMW E46 have their own little quirks. One of the more annoying problems with this car is the tail light fault. 

The issue was so persistent across different models of E46 that BMW went ahead with a recall covering all affected vehicles. But what if it happens to you now? Even though the recall is no longer in effect, we’ve put together a simple guide that will help you fix your broken tail light using nothing more than a simple kit.

The Source of the Problem – Broken or Faulty BMW Wiring Harness

Wiring harnesses have been the downfall of many an excellent car. There are plenty of reasons why wiring harnesses tend to cause problems. Some vehicles have insulation problems that often lead to ground issues. Others are plagued with water leak issues where rainwater gets into the harness, causing all kinds of trouble.

None of that is the case with BMW E46. This car suffers from a slightly different kind of wiring problem caused by hardware that isn’t beefy enough to handle the power being pushed through it. 

First Signs of Trouble – Rear Tail Light Failure Warning Light

One of the initial signs that something is off coming in the form of a warning light that appears on the dashboard. After overcoming the initial shock of warning lights popping on your dash, you’d probably pull over to check the lights in the rear. What you might find is that no bulbs are working or that they all are. Or maybe your entire cluster is coming on and off. 

Say hello to the faulty tail light issue. BMW has apparently decided to use connectors that weren’t up to the task. More specifically, the ground wire on these connectors has a hard time taking to load. As a result, you now have a hot point on the connector that tends to run hot and melt the socket within the connector.  

If left entirely unchecked, this issue will lead to connector damage and meltdown that can cause all kinds of symptoms and problems. However, the most obvious one is the light on the dash. Fortunately for everyone, fixing this problem comes down to the fairly easy replacement of the connector or possibly the entire bulb assembly where the connector plugs in. 

Symptoms of a Faulty or Broken Tail Light Connector

We’ve already mentioned that the dashboard warning light is usually the first indication of a problem. However, the symptoms associated with this problem can vary. Here are the most common ones you might run into:

• Warning Light/Working Tail Light Cluster – Getting the warning light on your dash only to find that your entire tail light cluster is working just fine is a possibility. This just means that the damage to the connector and the bulb housing wasn’t severe enough to cause any further malfunctions
• Warning Light/Faulty or Broken Tail Light Cluster – More often than not, you’ll find that the entire tail light cluster isn’t working in addition to the dashboard light. If this happens to you, you must get it sorted out as you’re risking not being seen at night.
• Warning Light/Intermittent Tail Light Functionality – Sometimes, not often, you might find that your tail lights are working intermittently. Again, this is a good enough reason to park the car for a day or two and get it fixed as soon as possible.

How to Perform the Tail Light Repair on BMW E46

To sort your tail light out and the tail light repair cost quoted by your local auto shop, you’ll need to get a few replacement parts. We’ve put together a list of necessary components so that you don’t have to dig around for info too much. You’ve got a few options on the table. There’s the repair kit 100K10107 that comes with both light bulb assemblies as well as the repair cables included.

One thing to note about this issue, in general, is that for some reason, the driver’s side tail light cluster is the one that’s predominantly affected. At least that’s the case for most drivers. However, since you’re already spending time dealing with this, you might as well swap both sides just in case.

In addition to our kit, you also might want to get the connector and the wire terminals. We’re mentioning these because both the wire terminals and the connector tend to get damaged over time. By getting all of these replacement parts, you’re set to start.

Step 1 – Remove the Bulb Assembly

The very first step is to pop the trunk and remove the driver’s side bulb assembly. It’s easy to do as you only need to pop it out. It may or may not take some force to do so, as the whole plastic assembly needs to come out. Once you’ve done that, flip the bulb assembly to reveal the electrical connections and wiring.

Step 2 – Unclip the Connector and Pull It Out

With the bulb assembly out, located the main wiring connector and pull it out. It’s held in place by a little clip right down the middle, like most similar connectors. Simply apply pressure to the clip and should pop right out. Now that the connector is unhooked take a closer look at each socket. There’s a good chance that the 3rd socket from the left is burned and mangled.

This is the moment you’ll know just how much this whole repair will cost you. If the only thing damaged is the connector itself, all you need to do is replace the ground wire and the connector itself.

However, if you take a closer look at the connector socket on the bulb assembly and burn damage on the 3rd terminal from the left, you might need to swap the entire housing. We’ve put together our repair kit for situations like these.

The ground pin slid right out. Notice the green corrosion on the wire also. This is exactly why the ground wire needs to be upgraded. That will be cut off and the new ground wire attached to it.

Step 3 – Swap the Connector

Swapping the connector shouldn’t be too much of an issue. The key is to remember the color-coding of the wires and ensure that each one is installed in the same order. Before we can do that, we need to sort out the ground wire that had caused the whole issue in the first place.

We’ll do this by first removing the burnt out terminal from the factory ground wire and replacing it with a new one from the kit. Then we’ll take the new ground wire with a larger spade connector and connect it to factory ground. Lastly, place the spade connector into the black plastic hosing to protect the connection.

Step 4 – Migrate the Bulbs

This last step is optional. Whether or not you should follow it depends on the amount of damage you’ve found on your factory bulb housing. If there wasn’t any, which is improbable but not impossible, you should be fine with a simple connector swap.

However, if you’ve noticed that there is damage to the socket, you’ll want to swap out the whole thing. Fortunately, this only means that you’ll have to migrate your bulbs on to the new part. Once done, put the bulb housing back in its place, and you should be done.

Step 5 – Do the Passenger Side

Our kit comes with two sets of replacement parts that will cover both tail light clusters. It’s up to you to decide whether you want to swap the other side too. 

Although this issue is not that common on the passenger side, it does happen. Spending a bit more time to swap out the connector, the ground wire, and the bulb housing is a solid preventative measure. Besides, you’ve already got the replacement parts.

How Difficult is This DIY Project?

Although it does require you to rewire a few things, the repair itself is not too complicated. Sure, you’ll need to strip a wire and install a new terminal, but that fairly simple. On the other hand, doing this yourself will save you quite a bit of money. Different auto shops charge different amounts, but the chances are you’d spend more than you would to cover the kit’s cost.

Does this Kit Fit All E46 Models?

As far as we know, most if not all versions of BMW E46 are affected by the tail light failure issue. That being said, you can always check whether or not your specific model is compatible with our repair kits. Simply head over to our online store and fill out the information about your car. Alternatively, you can use your VIN to be absolutely sure. If you’re still unsure or have any other questions regarding our kits, feel free to get in touch with our customer service using the form on the Contact Us page of our site. They’re standing by to help you with whatever questions you might have!