Why do car shops turn off the automatic setting of my lights?

[vito]

All three cars that I own have an "Auto" setting for the lights. Daytime running lights stay on in the daytime, and when it darkens the low beam headlights go on, and off automatically as needed. On one of my cars the headlights go on automatically if I activate the windshield wipers. For the most part I set these car's light swith on "Auto" when I take them home brand new and never feel the need to touch that switch again. Except.......when the car has been at the dealer or a repair shop. Invariably the mechanics turn the light switch to "off", but for what reason I have no idea. Since the car's engine is not running while it is being worked on, or having the oil changed, etc. except for brief periods, it cannot be because the lights coming on are too much to deal with in the shop. So I try to remember that as soon as I pick up the car I check the light switch.

Several days ago my wife brought our one year old Mini in for its first oil change at 10,000 miles, which is free for us as the owner (free routine maintenance for the first two years is included in the car's cost). Because she took care of the car I didn't remember to check the light switch. Yesterday I used that car to visit my daughter, leaving for the one hour ride home after it had gotten dark. Riding the interstate with a fair amount of other cars on the road I had only a slight sense that things were darker than normal. It wasn't until I left the Interstate that the road ahead of me was really dark! I pulled over thinking that one of my headlights had burned out, but the reality was the lights were in the off position so there I had been driving at 80 mph with just daytime running lights in the dark of night. I know its my own fault but it more than annoys me that all of these mechanics routinely do this on any and all of my cars.

 

[hittman]

A good mechanic will do that to check if all the lights operate.
A good mechanic with attention to DETAIL will set it back to Auto.

 

[WAYNO]

There are multiple reasons. Most of all, it's prudent to do so. Only my opinion as a mechanic of many years. I hate trusting electronics.

Next, the auto setting means different things on different cars. On some, auto means auto high/low beam. On some, it means automatic turn off. When you're in for service, and they test all your light functions, they go through all the positions and just settle on off when they're done. That's safer than leaving them on any other position and inadvertently draining your battery. Electronics have glitches. I've gone to my car long after it's shut off, and my interior lights remain on. Turn the key on and off, and voila, it now works as designed. I would trust headlights no more than this.

Finally, depending on if your doors are completely shut, and/or the progression of key functions, you could be left on accessory, where these automatic functions may not work as expected. This could really happen in a shop, where they're turning the key on and off, sequencing updates in service intervals.

 

[hittman]

Oh the stories we could all tell of things mechanics see ….. be a different thread for that.

 

[RoninPA]

On some production models the AUTO function would turn the low beams or driving lights on but NOT the taillights. I've seen, on the highway, at dusk to full night, people passing me and when they get around me, they have no tailights on and with the right color car, or in fog, they disappear.

 

[GypsmJim]

We can't answer your question. Why not simply ask your mechanic why he did it.

 

[GasGuzzler]

I do it 100% of the time. Fortunately GM cars have a spring loaded switch the returns to AUTO on its own.

If you want to know the reason it is because many of our tests are KOEO (key on engine off) and if the lights were to stay on, the battery would go dead during testing. If this happens during programming, a module can get bricked fairly easily.

Most techs will do a couple things EVERY time they pull a car in. One is defeat the lights, two is roll down the driver window.

It's not a big deal but they should put it back I guess.

 

[kentucky yeti]

I do it 100% of the time. Fortunately GM cars have a spring loaded switch the returns to AUTO on its own.

If you want to know the reason it is because many of our tests are KOEO (key on engine off) and if the lights were to stay on, the battery would go dead during testing. If this happens during programming, a module can get bricked fairly easily.

Most techs will do a couple things EVERY time they pull a car in. One is defeat the lights, two is roll down the driver window.

It's not a big deal but they should put it back I guess.

↑↑↑↑↑
This. Lights are on while working in the shop if you don't manually turn them off. A weak battery = a dead battery, possible fried electronics, and blinding coworkers across from you.

 

[beentheredone]

First thing a mechanic does before working on an engine -- disconnect the battery. Bye-bye to all driver-presets.

 

[weaselmeatgravy]

I always assumed it was simply because it is annoying when they come on as they pull it into the garage.

It always gets me though. I'll be driving around at dusk wondering why I can't see. Then once it occurs to me, I have to remember how to turn them on in whichever vehicle (our car, wife's SUV, or my truck) I'm driving since they are all different makes/years.

 

[Montelores]

Absolutely not trying to be snarky, but are we victims of automation?

If you're driving the car, you are responsible for it.

Monty

 

[Dan in MI]

First thing a mechanic does before working on an engine -- disconnect the battery. Bye-bye to all driver-presets.

There are various ways to prevent that from happening and most current mechanics know how. I just swapped batteries in my truck and didn't lose a thing.

 

[beentheredone]

There are various ways to prevent that from happening and most current mechanics know how. I just swapped batteries in my truck and didn't lose a thing.

Okay. Try leaving it disconnected for an hour or two ...

Most mechanics these days have to look up how to reset the "Service Engine" light -- if they even bother.

 

[AJGUNNER]

I recently went through the same thing. Drove about 20 miles on the interstate as the evening progressed. Car was 1 day out of the shop and had only been driven during the day. as I got off the hwy and hit the back roads for the next 10 miles, I figured out about 1/2 my dash lights were out in addition to not having any high beams. I was thinking I will make it home and then back to the shop in the morning to see what they screwed up. About that time is when I figured out I had been driving with nothing but daylight running lights. Flipped the switch back to auto and like magic I not only got headlights and high beams, but also got all my dash lights. DOH!!!

 

[WAYNO]

I'm glad you guys aren't airline pilots. 👨‍✈️ Ya might forget to turn on the auto-pilot.

 

[jimbo1096]

I would just ask the dealership service department then you will know from the source.

What I picked up on was the one year oil change. I know you said it only had 10K miles but the max service schedule I know of for oil is 5K miles and I would be concerned that at 1 year you have oil that is degrading, losing viscosity, picking up contaminant and acids that can harm your engine. Oil does not last indefinitely just sitting in the oil pan.

 

[Montelores]

New technology has increased the intervals between oil changes.

For example:

Honda Oil Life Percentage

You'll see "Oil Life" with a percentage number on your dashboard. This is your Oil Life indicator, a convenient and important part of your Honda's maintenance reminder system. With fresh engine oil, your percentage is 100%. It drops over time as you put miles on your Honda. So at 40%, your oil still has 40% of its lifetime remaining to do its job before it needs to be replaced. At 15%, your oil still has 15% lifetime remaining, and so on...

...When oil life reaches 0%, service on your vehicle's engine is now overdue. By driving with degraded oil, your Honda's engine may fail or significant damage may be caused.

Under certain driving conditions (high temperatures, short trips, frequent starts & stops, and hilly terrain) your oil life will degrade faster than under normal conditions at lower RPMs...

Honda Oil Life Percentage

Honda Oil Life Percentage

www.scotthonda.com

Monty

 

[GasGuzzler]

I would just ask the dealership service department then you will know from the source.

What I picked up on was the one year oil change. I know you said it only had 10K miles but the max service schedule I know of for oil is 5K miles and I would be concerned that at 1 year you have oil that is degrading, losing viscosity, picking up contaminant and acids that can harm your engine. Oil does not last indefinitely just sitting in the oil pan.

GM OLM can go as far as 7500 miles and time is hardly a factor. Gasser full size trucks use 0W20 oil too. This isn't 1991.

Okay. Try leaving it disconnected for an hour or two ...

Most mechanics these days have to look up how to reset the "Service Engine" light -- if they even bother.

What is your experience with MOST mechanics these days? Hopefully they aren't "resetting" the light EVER either. Should be clearing a code after a repair.

 

[hittman]

I think my 21 Silverado with a 5.3 calls for 7500 mile oil changes. I can’t do it but need to evolve LOL. It was drilled into my head 3 months or 3000 miles for so long its hard to change.

My dealership changes it for me at 5000.

 

[Kevin]

Yes, the 3 months or 3,000 miles is hard to get out of. For years, that’s what we were “taught.”

Since then I’ve have VW’s and currently a BMW, which go 10,000 miles between oil changes.

I suspect the Mini in Vito’s original post has a very similar warranty to the BMW. Full service for 4 years or until 40,000 miles. It really makes these cars a good deal.