2000 f-250 going haywire!! Help!
 

Here's a situation for the pros:

A good friend of mine has a 2000 F-250 Powerstroke diesel which runs very well but the electronics are going berserk!

It seems to be triggered more when its humid or after it rains. Sometimes the horn will honk constantly out of nowhere and has to be unplugged to stop. The dome light and power locks flicker uncontrollably at random moments and while driving, the guages flicker all over the place and the overdirve light will flicker as well.

You can hear the relays flickering constantly. Would it simply be a defective relay, bad ground, or defecive BCM?

An expert diagnosis would very much be appreciated before having the dealer charge an arm and a leg!

Thanks!

Only a suggestion, but moisture problems very common at the fuse block under the left side of the dash. Check both front and back of the block, especially if the windshield has been replaced.

This truck had been a rebuild after an accident years ago before the second owner bought it. There is a chance that the windshield had been changed. Any way to remedy the problem if there is a leak?