Why does my Miata hate me?

I decided to give the ND RF a little tidy, so I washed it and treated the plastics. The top has been creaking a bit, so I went about treating the seals with Shin-Etsu, and promptly discovered that there is a razor-sharp edge on the back lip of the top panel. I did this with my finger, which reacted negatively to the experience. I studiously ignored this expect to try to avoid getting blood on things I'd have to clean it off of later. Once I finished, I backed the car into the garage, then did a once over to see if I missed any spots of dirt (or blood), only to see that my right taillight is out. On closer inspection, my left front marker position light is out as well.

I scanned the system and got the following errors:

B1098: 11-0F Left position light

U3006: 16-0E Control Module Input Power A Circuit/Open

Where do I go from here? Where is the lighting control module located? I suppose the taillight could just be a bulb - I'll have to figure out how to pull that out.

OK, I understand now: it's possessed. I pulled the taillight out, but of course it's LED, so not the bulb; everything looked fine, all wires and connections clean and intact. Put it back in and decided to leave it for the moment while I do some research. Check it one more time and now everything is working.

I would like to have a look at the lighting control module connector, so if someone can point me to that I'd appreciate it.

You washed it.

Water intrusion?

In reply to Mr_Asa :

Nope, washed with quick detailer and microfiber cloths.

Per this site (which refers to the 2016 ND; hopefully my 2021 is similar enough for this to be relevant), everything runs through the Electronic Supply Unit (ESU), which is located up under the dash on the left side. I'll have to contort myself up under there and see what I can see. The exorcism I was planning might be the simpler option (and possibly the more effective one).

And the lighting issue has reappeared as before. I saw the front marker light flicker slightly, which points to a faulty connection somewhere. I guess I'm going to have to dig in and find the ESU and look over the connector. Bugger.

My guess is that a rodent took a liking to a wire or two or three somewhere near the noted module, but that's just a guess.

I didn't have much time to look into this this morning, but here's what I've found so far.

All the affected lights are on the same circuit (not surprising), which looks pretty simple. The problem is that the intermittent nature of the issue makes it hard to trace. As of this morning, everything is working. I verified battery voltage at the 20A fuse (also not surprising, since all the other lights work), but getting access to the ESU is a pain; in a very un-Mazda-like arrangement, there's a big block of rigid styrofoam blocking access to one of the nuts holding the cover on, and you have to pull the carpet to get it out. I'm seriously considering just drilling an access hole through the styrofoam, but I ran out of time to keep fussing with it today.

The only other possibility I can see from the diagram is ground point G05, which seems to be buried behind the front bumper on the left side, somewhere below the headlight unit. Again, no time to investigate further today.

In reply to einy (Forum Supporter) :

I suspected that as well, but so far I haven't found any signs of damage to the wiring anywhere. Not to say it couldn't be hidden somewhere, of course. I'll have to trace the harness from the fuse box to the module when I have more time to be sure.

Do you have any aftermarket electronic mods?  Those aftermarket roof /window controllers are pretty popular, and for good reason.  I didn't have any issues when I installed them in mine, but if I had issues like yours the first thing I would do is uninstall them.

At the opposite end of the Miata spectrum, my NA had an intermittent left front marker also, but it turned out to be a bad socket. Much more unlikely given the age of yours, but still possible.

No mods except for sway bars and door bushings. I don't think there is a socket per se, as the affected lights are LEDs. I think I'm going to have to trace that red wire from 4I on the ESU and see if I can find any damage; it's got to be either that or the G05 ground.