2010 XLT: All interior lights and horn stopped working after turning off the lights at the switch.

[Timbo]

OK, the horn I just noticed today, but Saturday night all my interior lights stopped working after I had manually turned them off, and it's not the fuse.  

I had both left side doors open (driver's and sliding), and decided to turn all the lights off with the switch above the rear view mirror, like I've done a hundred times in the past.  

That went fine, but when I tried to turn them back on, nothing happened.  

 

I thought I read somewhere that it might have something to do with a door switch?

About two years ago I replaced both my front door actuators, but I don't know if the switch is the same part or not.  

 

I did check the two, 7.5A fuses and the 10A fuse next to them, but they're all good.  

I know my inside lights and my horn are likely separate fuses, so that's another reason to rule out a blown fuse as the problem. 

 

I should mention that the lights won't turn on, doors opened or closed, when I manually move the switch above the rear view mirror to the ON position.  Also, the two smaller lights to each side of the front, interior light also won't turn on with their dedicated switches.  

 

Anyone else run into this perplexing problem?  

I hate electrical gremlins.  

 

-T

Edited July 7, 2025 by Timbo
Left something out.

[Timbo]

Never mind. I found the problem.
It was unbelievably simple. So simple, I’m embarrassed to say what it was.

Doing a quick search turned up all kinds of things that could be the issue, but in the end it turned out to be the horn fuse was blown.

I didn’t know the interior lights and the horn were connected to each other.

 

I rarely use my horn, so when the lights went out, I didn’t think to check the horn fuse.

Why would I?

 

Well, thanks anyway. I’ll post again when something else breaks and I’m too impatient to dig a little before asking an unnecessary question.

 

T