The Dangers of Experts Writing Documentation: A Real Life Example

There are some real, tangible dangers to having experts write documentation. Experts have the perfect tools, skip steps, know where things are based on experience, use jargon, have spare parts so mistakes aren’t a big deal, and as a result make terrible time & work estimates. This leads to confused, and subsequently angry, people, which is probably not what you wanted.

I was thinking about all this as I entered my fourth hour of installing a trailer wiring harness on my Mazda CX-9 today. It’s a unit from Curt Manufacturing, kit #56016. When my CX-9 was in the shop for an alignment a few weeks back I had them put a hitch on it. They got squirrelly & weird when I mentioned installing the wiring harness, though, and I decided that I could just do it myself some afternoon.

The documentation in the harness kit is horrible, the written equivalent of “just wire it up, duh.” Luckily they offer a YouTube video. Since I don’t do a lot of trailer wiring it seemed prudent to take five minutes and watch it.

One hour? That’s cool. I’m also wondering what “proper safety equipment and precautions” are. I guessed that their lawyers made them keep it vague so the onus was on me to figure it out, and absolve them of any liability. Whatever, I’ll figure it out.

I notice their tools have air hose couplers on them, and aren’t quite what people would have in their garage. These also aren’t the tools that were listed in the installation documentation. I pause the video and spend 10 minutes digging out my cordless Dremel, my right-angle drill (yeah, I actually have one) & my bit index, and 5 more minutes trying to find my 10mm socket which is the social butterfly of my socket set. Total time elapsed so far: about 20 minutes.

I also notice that the car in the video is on a lift, but they omitted a lift from this list of tools. This becomes significant later.

Begin by opening the back hatch. So far, so good.

Remove the floor coverings, storage trays, and rear scuff panel. The woman in the video pops all that stuff out in 5 seconds on the video. Things she didn’t cover include the mystery of the fasteners keeping the storage trays attached to the chassis, five additional panels she didn’t remove but are in the way for me, and the subwoofer back there with its 400 bolts. Back to the web, and luckily eTrailer.com has a 10 minute video on this same topic and doesn’t skip these things. If you ever write documentation these are the sort of details that really matter. Total elapsed time: 50 minutes, and that’s with the help of my Milwaukee impact driver, which also wasn’t on the tool list.

Disconnect the negative battery terminal. Done. 55 minutes.

Remove the rear cargo loops & Phillips screws. Luckily the other video I found had advice on this, because the woman in the Curt video took 10 seconds to pull these things out of their CX-9. I’m up to 65 minutes.

Disconnect the taillights and insert the wiring harness connectors. This seems straightforward but in the video the rear vehicle trim stays popped out so the woman can work on it. I conclude she must have a prehensile tail.  Us normal humans use a scrap 2×4 cut to hold the panel open. Elapsed time: 85 minutes. Note that “miter saw” and “2×4” are not on the list of tools.

Route the green wire over to the other side and hook it up. The other video had good advice on this, too, as there were nuances completely skipped by the Curt video, and by the time you’d realize that you’d have everything all closed up already. 95 minutes.

Grind off some paint, drill a pilot hole, and use the included screw to connect the ground wire to the chassis. “Be mindful of what you drill into and what is behind it.” No kidding. I love my Dremel, by the way. If you get a Dremel get a cordless one with a lithium-ion battery (so it holds a charge over time), the engraving handle accessory (I never take it off), a combo pack of bits, and extra cut-off wheels. You will be unstoppable. 100 minutes.

Find a suitable mounting location for the converter box, and use the tape to attach it to the chassis. Unfortunately for me my CX-9 has a whole gob of mechanical stuff right where she stuck her converter in the video, so I have to figure that one out. In the process I also notice that the green wire is looped outside something where it shouldn’t be, so I have to go back to the other side, unwire it, and rerun the wire. 120 minutes.

Strip the power wire and use the included butt splice connectors to crimp the fuse holder on. No sweat. 125 minutes.

Remove the positive accessory nut on the battery cable. Connect the fuse holder’s eyelet to it & refasten the nut. Done. 130 minutes.

Route the black power wire down past the engine block and towards the back of the car, keeping away from moving parts and excessive heat sources. Um, excuse me?

I mentioned this before, but perhaps you notice something peculiar about the woman in this image:

Yeah, she’s standing underneath the damn car. As I am neither 6 inches tall nor in possession of a car lift I go and get my set of vehicle ramps and get the Mazda up on it. I don’t consider myself an idiot but I can only guess what gets hot or not under there. She ties her power wire to some HVAC connections, but I surmise that one of them probably gets hot at times.

The other video runs the cable from the trunk side first, and in looking at things that seems like a better plan, so I take it all apart, cut the splice connectors off, and run it through a rubber grommet in the trunk. There was some black silicone sealant in the kit which is never mentioned anywhere, so I use that to glue the grommet back down so the cable doesn’t move & rub & short out, and to coat the ground wire connection I made earlier so the chassis doesn’t rust there.

I end up taking that black tray you see behind her hands off the car and running the cord through there. The kit includes the world’s worst zip ties, especially when you’re upside down under a car, and about half of what I used, because I absolutely don’t want this wire snagging on something, nor being an obstacle in the future when some mechanic is hacking away at the car. At this point I’m wondering why I don’t just plug this into the accessory outlet in the back, but trailer wiring is often sketchy, especially for boat trailers, and I’d rather not blow my accessory fuses.

In the video it takes her 11 seconds to do this. ELEVEN. SECONDS. Total elapsed time for me, out here in this hell I call reality: 210 minutes. That’s 3.5 hours, and they said it’d take me 1.

Locate the rubber grommet that gains access to the trunk. Punch a hole in the grommet and run the wire through. Yeah, I did this already.

Strip the power wire and use a splice connector to connect it to the converter box. You have got to be kidding me — I don’t have any more butt splice connectors. I ponder riding my bicycle to the hardware store but I carefully secure everything, reconnect the battery, and drive over there. I look like I’ve rolled around under a car all day, which amuses the staff. Local hardware stores rule, by the way. Try asking a Home Depot employee where the butt splice connectors are and you’ll get a blank look and a “this isn’t my department” comment (to which I always retort “so why are you standing here, then?”). I was in & out of my local True Value in 2 minutes. Anyhow, 230 minutes, and I now own 47 more connectors than I need.

Route the “four flat” under the trim. Replace any previously removed vehicle parts. Put the fuse in. Test it using an electrical tester or a properly wired trailer. I love how they use jargon here, “four flat.” A few more seconds and their demo CX-9 is all back together. It takes me more than that, I mess around and find a better way to route the connector through the spare tire area so that it can be stored out of the way. They also don’t mention that getting the interior of the vehicle reinstalled means 15 minutes of fighting to get it underneath the trunk door gasket again, which is hard because it’s squirrelly. I end up using some levers designed for changing bicycle tires.

Total elapsed time: 270 minutes. 4.5 hours.

It’s one thing to let experts write documentation, but it absolutely needs to be tested by novices. What would have helped here?

  • A video that isn’t abridged. Show the whole process, even if it’s long. Do not skip any steps.
  • Better paper documentation and a complete list of required tools.
  • Acknowledgement that at some point you are going to need to be under the vehicle.
  • Documentation for all the parts in the kit. Nowhere did anything mention the silicone sealant, so at the end you’d be left wondering if you screwed up.
  • Spare parts in the kit. A couple more splice connectors and more higher-quality zip ties would have helped immensely.
  • Better time estimates. Frankly it would have been better to omit the estimate altogether than seriously understate the time committment like they did.

Better product design would have removed the need for a lot of this, too. As it turns out the CX-9 comes pre-wired for trailer wiring, and a product that plugs directly into the harness in the back would have saved immense amounts of time under the car. In the future I know that’s the route I’ll go in the future, choosing the more expensive OEM part that is way easier & faster to install. Opportunity cost is a real thing.

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