Some bad designs are noticeable right away, their poorly-considered executions slap you in the face like a slice of wet ham. Others are more insidious, with problems lurking stealthily under the surface. The Cadillac XLR’s taillights are an example of this latter group, and they’re causing the handful of remaining XLR owners all kinds of expensive headaches.

In case you’ve forgotten, was essentially a Corvette in a crisply tailored Cadillac suit, and with a better interior. GM built these expensive cars from 2004 to 2009, and they had many innovations, including being Cadillac’s first car with adaptive cruise control and seats that could chill or toast your buttocks. Also, they had some fancy LED taillights.

As a lifelong taillight fetishist (don’t kink-shame) I had noticed these lights before, as they are bold and handsome, but I didn’t realize the depth of their problems until I saw this tweet from our pal Bozi:

Wait, what? I needed to know what was going on here, this strange situation of hyper-valued taillights. I did a bit of research and realized that, while Bozi’s tweet was a bit of comedic hyperbole, it wasn’t really all that far off. Look!

What the hell is going on here? $ to $ for a freaking taillight? What are these things made of, saffron, rubies, and cocaine?

Not exactly. What they are made of are LED strips and printed circuit boards, both of which are becoming fragile and failure-prone as they age, and with a deadly combination of GM not producing replacement parts and a very repair-unfriendly design, the result is absurdly high prices for replacements.

This is especially bad because taillights are one (or, I guess usually two) of those things that, legally, you have to have working on your car to register and drive it. It’s not like the XLR owners with bad brake lights can just opt to leave it broken—if they want to keep driving their cars, they have to get these lights working, somehow.

realizing how boned they are, and frustrating attempts to find replacements. Some have attempted to repair the lights, and in doing so you can see the full depth of the terrible design decisions made when designing these lights:

This thing is like an object-lesson in how not to design something you don’t want to be disposable crap. There’s no screws or fasteners to easily gain access to the internals, you have to heat up glue to 220 degrees just to get the lens off, and when you do, you’re greeted by a whole bunch of non-removable LED units and a printed circuit board with a coating on it that makes it near-impossible to repair or replace components, assuming that you even had the skills and knowledge about how to deal with dense, modern, surface-mounted semiconductor components.

What’s baffling is that this is a taillight, one of the few components remaining on modern cars where it’s expected that an owner can perform basic maintenance.

Most cars still have access panels so owners can replace failed lamps or LED units in taillights with minimal trouble, because these minor failures can lead to not being able to legally drive your car. Also, you know, safety and such.

I thought at first it should be possible to gut the internals of a broken XLR taillight and just rig up a simple set of replaceable LED units for brake, tail, turn, reverse, and side marker lamps, maybe using aluminum flashing to make a housing/reflector structure.

Doing so would assume that the wiring harness for the taillight had discreet 12V wires for the different taillight functions; however, when I look at the connector diagram, that appears not to be the case:

It looks like the connector is just sending signals to that circuit board, which has a small embedded computer to interpret those signals and translate them into whatever combination of lights is needed. I think that’s what’s going on, at least—all I can tell is that it’s not as simple as a wire per brake lamp, tail, turn, etc.

I think it might actually be cheaper and easier to just wire a whole parallel small wiring harness from the brake light switch, turn signal switch, and light switch than it would be to fuck around with any of this mess. Or maybe you could program an Arduino to read the signals and interpret them properly?

This is just ridiculous — it’s not like the taillights do any fancy LED animations or anything like that — they work pretty much like any taillight from the 1970s and up, just needlessly complicated.

I think this is worth pointing out not because we have such a huge percentage of XLR owners among our readership, but because bad design like this—specifically, owner-hostile design decisions like these—need to be called out.

These XLR owners love their cars and likely want to enjoy them as long as possible, but this needlessly complex and unserviceable design is making their lives actively worse.

Things like taillights, that are legally required and are prone to damage (they’re often right at the exposed corners of your car, highly vulnerable in case of even a minor fender-bender) need to be easy for owners to service, especially as the car ages.

Designing taillights like these, with nearly zero capability to be serviced by the owner, cheaply and easily, show actual contempt for owners by the engineers who designed them.

So, screw you, GM, and these stupid, overpriced taillights. Please don’t pull any shit like this again. And that goes for all you other automakers, too.

I’m watching you. ALL of you.