Just bought a new-to-me 1997 F350 SRW Reg 4x4 w/ 7.3L diesel. This is a beautiful, bone stock truck and runs like new. The previous owner garaged and pampered it it's whole life.

Anyway, I was taking a good look at everything and noticed this module / harness was unplugged under the dash, right above the gas pedal. The plug was just hanging there. What is it for?

 

False alarm! I punched the part # thats stamped on it into the search and came back with this thread:

https://www.ford-trucks.com/forums/7...10d840-aa.html

Looks like it's for the seat belt chime?

 

Quick! Smash it!

 

It's also your key-in and headlights-on chime.

 

Most people unplug that module simply because the key chime is annoying, but if you want to keep the headlight warning intact you can disconnect the key sense and/or seatbelt sense circuits then plug the module back in and still have just your headlight warning chime.

 

Annoying it may be, but the number of locked up keys & dead batteries in this world says it serves a purpose.

You can put in a toggle switch that allows you to shut it off when you need to leave doors open.

I got one on the key tumbler ground wire.