The changing thickness of manuals

[Bill (Smithville NJ)]

(12-07-2022 07:27 PM)Jeff_Birt Wrote:  Searching online revealed that on some years of cars Mini chose to make the light indicate an error condition and on other years it indicated normal operation. Brilliant. The owner's manual was useless as it never just did come out and say what the bloody light meant. I had to get out my scan tool and interrogate the passenger seat weight sensor to see when it sensed no passenger, a small passenger and a regular passenger. Then I could watch the status of the light while looking at sensor data to divine what the bloody light meant.

Turns out the light was illuminated when the seat was in 'normal' condition and off when the airbag was deactivated. One clear sentence in the owner's manual calling out the function of each idiot light would have made it abundantly clear.

Reminds me of the control panel on the Three Mile Island Nuclear Plant. During the testimony of the Presidential Commission on the TMI accident, a control operator was asked to describe what he did when he came on duty. He said his first job was to verify that the control panel was in the correct operation. He said he did this by picking up the control manual and then verifying that each light was showing the correct signal and that each switch was in the correct position.

The control panel was NOT designed to show all green lights when operating within parameters. So some would be green when in parameter and some would be red when in parameter. Thus the the need to compare the panel with the manual.

Just a side note: Whenever the TMI had an error, it would quickly cascade into many hundreds of other errors. The control operator said the printer was so slow that it would get so far behind in printing the errors out that they would just unplug the printer and then turn it back on so that it would begin printing the currently occurring errors again. Of course they then lost the history of all the errors.

Hopefully newer Nuclear Plants have better designed control boards.

73
Bill WD9EQD
Smithville, NJ