I’ve already shown you how to replace the rear side marker bulb on a MINI Cooper R56. But what if you install a new bulb and it still doesn’t work? Some additional troubleshooting is required. If you find yourself in this predicament then this post is for you.
MINI Cooper will light up the dashboard with warnings any chance it gets. Several pages in the manual are dedicated to those lights. But the side marker lights are not considered essential so you won’t see a warning if one goes out. You’ll just have to periodically check the car yourself, like in the good old days.
Let’s say you found that one side marker light is not coming on. You’ve swapped in a proper new bulb but it’s still not working… Now what do you do? Her is how I went about fixing the problem.
First step was to confirm that there was, in fact, no power at the pin into which the bulb holder plugs in. For that I used a voltmeter (aka multimeter), a pair of alligator clips and a couple of homemade probes made from a paperclip. Stick the probes into the pin holes and measure the voltage. I did it on both the working and non-working sides just to be sure I was probing the right pins. Working side showed 11.07 volts while the non-working side had 203 millivolts – meaning there is no power at the pins.
Great… so now what? Do not do what I did – wait over a year before trying to tackle the problem again. With other projects higher on the priority list I disconnected the working side bulb. I did that to pass state inspection. One of the things they check is that all OEM lights work. I know that because years ago I brought a Toyota Corolla that had a cracked fog light and they refused to pass it. I grabbed a screwdriver, went to the parking lot, took both fog lights off and asked them to reinspect. The car passed with no issues.
So over a year later I decided to troubleshoot a bit further. Sometimes a bulb connector goes bad. There is an easy way to test that. I stripped a bit of insulation from the wire right behind the connector and used a test light to see if there was voltage with the lights on. My test light didn’t go on. There was no power.
At this point I ruled out the bulb and the bulb connector so there was obviously a bigger problem in the wiring somewhere. But where? Wires just disappear behind a wheel well on the MINI Cooper. How do you trace it without disassembling half the car?
The answer is that you don’t.
- I waited another year to tackle the problem and
- I disassembled half of the car… or at least the rear bumper.
To be honest, after determining that the problem was in the wiring I all but gave up on trying to fix it. Unlit, the rear side marker can pass for a pair of reflectors anyway. I really didn’t feel the hassle of tracing the wires was worth it.
But then I decided to start towing a trailer with my MINI Cooper. To do that I needed to install a hitch. And to do that I needed to take the bumper off.
You can find instructions on how to take a bumper off the MINI Cooper in the link above. It’s straightforward, though I can’t say it’s easy.
Once the bumper was off it was clear why I wasn’t getting any power at the bulb. Here is the culprit circled in red – this is the wire that was cut in half somehow:
No idea why this would happen. There is no flexing in this area. Nothing sharp that could cut the wires.
I had two options: replace the entire wire or fix the break.
To get a new wire you need time and money. Plus even with the bumper off I couldn’t tell where the wire went and where it presumably plugged into the main harness.
There was just enough slack to clean up and solder the broken wires together. You could also add another piece of same gauge wire to extend it but in this case that wasn’t necessary.
I used a couple of quick clamps to hold the wires together and used a soldering iron to permanently repair the connection. I could’ve used a couple of butt splice connectors but I don’t trust them in auto applications. The last thing I want is having to take the bumper off again due to a connection that loosens over time. I’d rather spend the extra 5 minutes now to never have to worry about this wire again.
Soldered together and wrapped in heat shrink tubing this connection is as strong as new.
After a quick test (see the bulb glowing above?) I put the car back together. While the repair itself is simple, getting to it is not. No wonder it took me more than two years to fix this problem.
Hopefully this post gave you enough information to decide if you want to tackle it yourself or just leave it as is.
If you do end up taking the bumper off consider adding a hitch to your MINI Cooper as it won’t ever be easier than now – just 4 bolts! Even if you don’t plan to tow a trailer, a hitch will give you plenty of options for carrying cargo. A hitch mounted bike rack or a cargo platform may save you from having to buy an SUV. And anything that helps me to keep the MINI is a win in my book.
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