AskTog has possibly found the Worst Interface Ever. It’s a particular aftermarket pump you turn on that circulates fluid through the transmission of a Lexus SUV so that the gears stay lubricated if you are moving the car while the engine is off, i.e., while it is being towed. This is because if the transmission doesn’t stay wet, it can be destroyed.
Inversely, the pump must be turned off before the Lexus is to be driven, or the fluid won’t get to the the operating transmission and the transmission will go bye-bye.
So here’s the kicker – the only thing between you, a dead tranny and a $5,000 repair bill is a small switch that turns the pump on and off.
This Switch of Good and Evil, Life or Death, is hidden under the hood of the car. The switch can only be professionally installed and therefore can be in any location on the engine or in any orientation.
Ooo, but it gets even better: the switch is not labelled. You can’t tell whether it is ON or OFF just by looking at it.
AskTog has mitigated the problem by labelling the switch himself and running rigorous pre-tow and post-tow checklists, something that any normal person would naturally do if he were… say, a frickin’ astronaut flying to the frickin’ moon.
The moral of the story is as follows: “Never, ever, ever let systems-level engineers do human interaction design unless they have displayed a proven secondary talent in that area.”