One reverse light out, not the bulb, not the fixture, turned out the FRM turned it of
 

New to the forum but have had my hands in automotive electrical for a spell. Picked up a 2011 Mini Cooper S Hardtop. Under a prior owner the left rear fog+reverse assembly had been switched out for... ok I don't know exactly what happened but:

(1) unlike the right-side assembly, there was no reflector in this one. (?!?)
(2) it was full of water.

Enjoy a laugh at my expense -- I found out about the water when removing the thing, from below, looking straight up at it. Yeah, I took an impromptu shower. That was fun. :lol:

Because the lamp assembly itself was weird I bought a new one from the Mini dealership. No need to troubleshoot the old lamp assembly, bulbs, etc. They're history.

Anyway, there was obviously corrosion in play. The socket on the pigtail had corrosion coating the *plastic* so I spent a good amount of time getting as much corrosion as I could off of the pigtail. I figured out how to probe each wire terminal -- in order to determine (using a multimeter) whether inserted male contacts (sub in a sewing needle -- works great) are making good electrical contact with the terminals. They are. That's the good news.

The bad news: it honestly looks like none of the 3 wires in the pigtail are getting +12V, and I have no idea where to start looking to fix that. The car knows something is up; I have a warning indicator on the dash and the associated CC-ID code is 117, "Reverse Light Left Failure." That warning has been there since before I bought the car, and persists even with the new lamp assembly.

Does the left reverse lamp have a separate fuse from the right? I couldn't begin to guess from the icon pile on the passenger compartment fuse door or the one in the engine bay.

Separately, this is a 2-bulb assembly on both sides of the car. The second bulb in each was already installed when I got the car. In fact, even the new assembly I bought came with 2 bulbs preinstalled. The 2nd bulb is behind a red lens and does not seem to come on as tail light, brake light, or turn signal. What is it? I do not have a rear fog lamp switch -- are these bulbs rear fog lamps and present just in case one has the option? **EDIT** I figured out the answer is "yes" to this Q :)

Any insight or ideas on the left reverse light welcome; I have Googled and forum-searched for over a week and no dice figuring this out.

Update: spoke with someone at the local MINI dealer and no fuse, says it's a direct wire from the footwell control module, and upon detecting a short condition the FCM will shut the power off. Repeated detections cause it to shut the power down for good. Also said that they can try to tell the FCM to turn it back up, but in their experience sometimes (not always, just sometimes) the FCM may have to be replaced.

I'll report back results for posterity.

I had the exact same problem, water in the left lamp assembly. It corroded the internal stamped metal connections to the connector pins. I bought a new assembly, plugged it in, and all has been good since. I did squirt some hot glue over the pins where they go through the plastic to the connector so if it leaks in the future it won't get into the connector on the wiring harness.

The three pins are a Ground return path for both bulbs, a +12 for the marker light, and +12 for the reverse light, each activated as appropriate. So if you are seeing +12 on one of the pins with lights on, and +12 on another when in reverse then the footwell module is not a problem. Check continuity on the GND pin, which is which will be obvious from looking at the internals of the fixture. Check that the connector is properly seated, and use some contact cleaner and if necessary a small piece of wire to clean out any crud.

Thanks for the reply. Much appreciated -- especially that electrical detail. It confirms what I thought I had sussed out about what each wire was doing, etc.

Upshot is that the wiring was good. Between replacing the fixture completely (since the old one had no reflector -- beyond weird -- it had to go) and dissolving the rust off the pigtail (white vinegar soaking was my friend) I got the wiring 100% square. No continuity issues. And confirmed that +12V was not there, so the problem was either the FRM or something in the wire upstream.

The conclusion: Mini dealer told the FRM "yo, turn the danged power back on." Or, in more precise technical terms, cleared the related short circuit counter. Annnnnnd... boom, left reverse lamp is back in business.

Not bad for $60. And now that I better understand how much this car is basically a computer system with an engine, wheels, locks, and lights, my next project is digging into the various programming tools out there. Despite how weird it was to learn about all this, it's kinda cool :)

Well I learned something today. Yesterday my neighbor told me that my left back up light was out on my new to me 2014 Clubman. After reading this thread over and over, I went to work on the left taillight assembly.

To make a long story short, after a few beers and a lot of thinking , I finially figured out that it only has one

right back up light. I guessed that the left bulb is a rear fog light .

I've never seen one on an American car, but I did remember seeing a Mercedes SUV a couple years ago with a bright red light on the left rear of the car. Never knew what it was until now.

I learn something new about this car every day thanks to this forum .....L.J.