Interior lights staying on 79 deville

[79lac]

Hello all,
Looking for some direction regarding my interior lights. they are staying on all of the time. I already replaced the headlight switch and tested the door pins. Any ideas?
Thanks!
Jared

[79lac]

need some help! i would be ok bypassing my IES module if possible.

[carnut]

Usually a blown yellow 20 amp body or CSTY fuse will back feed and keep interior lights on . Most times this fuse blows because either a cigarette lighter shorted or theres tin foil, a dime, metal etc in a lighter socket or a cell phone charger was used and it drew a spark when removed. Use a test light on all underdash fuses, key on, car off. Most times the power door locks will not work as well, but not always.

[1980coupe]

Originally Posted by 79lac

Hello all,
Looking for some direction regarding my interior lights. they are staying on all of the time. I already replaced the headlight switch and tested the door pins. Any ideas?
Thanks!
Jared

hi, don't know if you have resolved this or not but I would say your illuminated control module is bad. This is found under the front driver side speaker. You would have to remove the dash bezel(woodgrain) and remove the wiper, and headlight switch to have some room. It should be white in color. Try this, get in the car, close door, and listen for a click sound where I told you, if you can hear it and lights are still on, then this is what probably is bad. I can hear it in mine so maybe you can too. Let me know of anything else I can help. I got the service manual, electrical, vacuum diagrams as well.
Good luck!

[carnut]

Have you tested the fuses, looked at the lighter sockets??