... we could have done better, but there's no reason any customer should be a jerk.

Warning lights can be both confusing and conflict-provoking by their very nature.

A woman and her husband once brought a Buick to my automotive department that they had been diagnosed with head gasket problems because of an annoying cold misfire. She worked at a state institution, so she was qualified to have work done.

Because of the previous diagnosis, they were prepared to pay for a fairly expensive repair, but a proper diagnosis and an injector cleaning took care of the problem.

During the process of the work, they decided to have the thermostat replaced, since the 3.1L was running a bit cold.  When my automotive student (a man in his 40’s) completed the job, he did everything right with one exception – he neglected to find out why the ‘LOW COOLANT’ light was on, and he had gone for the day when the couple came to retrieve their car.  Since I trusted the student as fully as I did (he had always done really good work), and since I knew the system was full of coolant when he was done and the cooling fan worked, I didn't drive the car after he was done with it. Maybe I should have.

The owner noticed the low coolant light was on and looped back around to the service door so as to air his frustration. He spilled out of the car with an attitude, all the while accusing the student of ‘forgetting to put coolant’ in his engine.

Never mind that we had saved him several hundred dollars on the job. 

Well, it turned out that some trapped crud had been disturbed during the coolant refill process and it had fouled the coolant level sensor, that little float in the recovery bottle on that particular car that's supposed to give early warning of low coolant concerns – the radiator and recovery bottle were both at their max fill levels with good clean coolant, but the warning light was indicating otherwise, and he made a real fanny out of himself with all the angry shouting he did about it.

And for what? So I would say 'no' the next time he came to ask for work?

Another delightful customer was a man whose wife worked at a nearby school, and their 99 Ford had starved for oil and destroyed the 5.4L engine.  I don't know if the warning light had come on or not, but she drove it one day and parked it and the next morning it was locked up.

  They had expected to pay from 6 to 10k to have that one straightend out, but we fixed it for about $3500 with a crate engine from Ford.  First we yanked the original engine and pulled the oil pan to see what had happened.  The bearings were welded to the crank.  Then we waited  a day or two for them to decide what they were going to do.  Then we got the okay and I ordered the engine.  It was drop shipped from Ford's parts depot in Atlanta, but it took about a week to get it.  By that time the truck had been in the shop for two weeks. The new engine would have a 3/36 warranty from Ford Motor Company.

Two weeks later when the new engine was installed (students don't work as fast as professional techs, I'm sorry!) and was done but for the ironing out of the peripherals (it was about a day from being complete), the student who was the chief operative didn't show.  The owner of the truck called with an attitude, wanting to know when his truck would be finished.

"Probably later this week," I told him. "..the student who has been doing most of the work isn't here today."

"Put somebody else on that job, but I want my truck back NOW!"

What a jerk.  I waited until the next day.  The job was finished.  The guy paid his bill and picked it up along with the warranty papers I had filed with Ford, then came back complaining about a transmission leak.  The student replaced the dipstick o-ring to repair the leak and replaced the crank sensor connector (the old one had a missing terminal retention tang and might cause a no-start).  The truck left and stayed gone for most of a year.  One day my phone rang.

"Can you check the engine you put in our truck?  It's making a strange noise."

"No," I told her,  "and there are two reasons.  One reason is that Ford Motor Company has warranted that engine for 3 years or 36,000 miles.  The other reason is that I won't deal with your husband any more... period."

It seems that some people appreciate the things we do for them and some just can't understand that we can say no to anybody who acts like a jerk.