Headlights stay on after truck and lights are turned off.

One thing I want to mention all three of my vehicles will leave the light on after I shut the engine off, it is a security thing. My Chrysler 200 lights will stay on about 2 minutes.

https://www.youtube.com/watch?v=fjunXA5aRqU

https://www.lifewire.com/car-headlights-wont-turn-off-534834
From owners manual below page 5-102
Headlamps The headlamp wiring is protected by four fuses. An electrical overload will cause a lamp to go on and off. If this happens, have your headlamp wiring checked right away
https://my.buick.com/content/dam/gmownercenter/gmna/dynamic/manuals/2004/buick/rainier/2004_buick_rainier_owners.pdf

I would check every single fuse in the car. Blown fuses can cause weird issues like this. While the initial issue with the mechanic does sound like an alarm problem....the rest does not unless the shop that installed it really butchered the job.

Switch.

This can be caused by a bad fuse, or a fuse with corroded or poor contacts, or a faulty headlight switch, or a problem with your wiring. Start with the fuse, then try turning the headlights on and off a few times to see if that helps. Otherwise, into the shop ...

Fuses, check all of them. Check relays, sometimes tapping with the handle of a screwdriver will get a faulty one to work intermittenly. Check dimmer switch and light switch. IF you have driven through water with leaking headlight benzels/covers, then water may have blown both. Im leaning towards fuses/relays or light switch.

possible problem head light relay or ground wires problem

On the components, you might try a separate ground. See if that helps? Check the battery negative connections. I've seen this even on newer vehicle where instrument cluster or whatever would dim a little when you turn on headlamps. I think it's a ground issue? Just my opinion.
On any component that doesn't work, check voltage and ground, you could try a redundant ground.

Any time you get any check light, you should
be at a repair in a couple of days, or at least
check for codes. Still need it diagnosed and
repaired in a week

Otherwise you waste gas,polute the air or could
cause some damage,as you don't know what the issue
is that set the light

The fact the check light went out, doesn't mean
the problem went away.

Don't clear any codes you find,their needed to diagnose
the system faults

That is so weird, because my 2004 Alero was doing the same thing a few weeks ago. I took it one morning to the auto place because I was really worried, but it didn't do it again while at the shop. It hasn't done it as badly as that one morning, but it occasionally idles a little high. Still haven't been able to figure out way.

Has anyone figured this problem out? Our 2002 Sable just started this as well...instrument cluster lights out, turn/hazard lights on when the headlight switch is turned on. This has the auto on/off switch with fog lights. This is happening in the auto and manual on mode. Any solutions would be appreciated.<br />