Interior lights not working properly

[Shade Tree Mechanic]

I have recently acquired a single cab 97 K1500. In my endeavor to get the power mirrors working, I have ran into a cascade of issues. Starting out, I found the fuse missing for the power mirrors. I replaced the fuse and the mirrors work now. Of course, the fuse controls interior lights as well. Shut the doors to celebrate my victory and noticed the interior lights still on. My only guess is the fuse was pulled to keep them off. Checked headlamp switch dimmer, not the cause. Moved to door ajar switches. Just went ahead and replaced them considering I destroyed them getting em out. No change. Thought I would try the dome override on the headlamp switch. It didn’t work. This led me to replace the headlamp switch. Now the override switch works and turns interior lights off when it’s pushed. Here’s where it gets gray. With the truck running, I shut the doors and the interior lights go out as intended. Open door and they come on. All is well and operating properly. Thought “hmm must of worked itself out” and turned the truck off and shut the doors to go inside. Well, well, the lights were still on. So, now my current situation is, interior lights operate properly with truck running and operate improperly when truck is off. Could this be an ignition switch problem considering the interior lamps work properly while the ignition is in the on position and not when it’s in the off position? 

[richard wysong]

could be the timer/relay, in the electric panel above your left foot

[Shade Tree Mechanic]

12 hours ago, richard wysong said:

could be the timer/relay, in the electric panel above your left foot

What is the function of this timer relay? Is it kind of a “truck off, shut doors, light turns off after 30 or so seconds” kind of thing? 

[richard wysong]

yes

[Shade Tree Mechanic]

Well, patience IS a virtue. I had no idea about a timer relay. After waiting patiently after shutting doors while truck was off after roughly 20-30 seconds, the interior lights went off. Thank you Richard for the help! So glad you pointed this out before I threw another part (ignition switch) at it! Now to go put the column shroud back on.

[richard wysong]

glad I could help, Thanks for posting the results, too often we never hear back on what the problems cure is

[JustRangerThings]

On 4/26/2022 at 10:45 AM, richard wysong said:

could be the timer/relay, in the electric panel above your left foot

I didnt know these trucks had timer relays. Which one is it? I'd like to add it to my truck, mine just shut off instantly.