Sounds like it could be the seat belt warning for driving without your seatbelt on. If you have your seatbelt on, then you have an issue with the switch or wiring.

 

Are there any persistent warning lights illuminated on the instrument cluster? If yes the owners manual would identify that signal.

It could be the self-test the PCM goes through during first start up----although I don't think five chimes five times in a row is normal. Apart from a possible alert to some sort of small malfunction it doesn't sound serious other than it being annoying.

 

 

My 99 SD F250 does this occasionally, I still haven't figured out why it does it. I just learned to ignore it.

 

The answers are in that ^^^ thread!

 

Screw that. I'll just continue to ignore the low pitched beeps. Too much work to replace that bulb. But thanks for posting that link. Now I know what it is. Been wondering about it for 5-6 years now.