I had a problem recently with the horn staying on when I took the Beta Coupe out for a run and needed to warn a magpie to move off the road. I had to pull over and remove the horn relay to shut down the noise which I must say is incredibly loud from the two air horns when you open the bonnet! The clear plastic fuse box cover disintegrated in my hand into several pieces when I removed it. I knew it was in poor shape as it had six or seven spider cracks at last count.
I have previously replaced the horn relay not that long ago because of the same sticking on problem but I suspect in this case the problem may be the horn push not disengaging the horn circuit contacts. Worn springs perhaps or some other adjustment problem? I need to investigate the cause further. The steering wheel fitted is not the original but an Autotechnica after market one which did require a lot of fettling and fabrication of replacement parts on a lathe by the auto electrician who fitted it for my father. Some of the original horn bits which came with the steering wheel were of poor quality and not sufficiently robust or durable, hence the replacement parts fabrication.
Anyway, the fuse box cover is probably beyond repair with so many cracks and after an internet search, I concluded there is an extortion racket operating in the supply of used Lancia Beta fuse box covers, especially on Italian ebay! There are also numerous different main fuse box cover versions in existence with different relay layouts and sometimes blank spaces. I observed at least three different relay placement versions. In the end I settled for a relatively inexpensive 3D printed version copy of the exact same relay layout cover that is fitted to our Beta Coupe. It was produced by an enterprising chap in the US who works in the 3D printing industry and makes a selection of rare classic car bits on the side that can be copied by 3D printing.
The 3D copy is not clear like the plastic original, more a translucent finish with a slight textured surface. Any imperfections in the original cover are also reproduced in the copy. But it is a practical and relatively economical replacement solution. I was wondering whether an enterprising UK based forum member with knowledge of or connections to the 3D printing business might be interested in making a batch of these 3D printed covers for forum members and for future sale on Mark Wastnidge`s Beta parts website. The better the sample original cover condition wise, the better will be the final 3D copy. This would save on expensive postage from overseas and free everyone from extortionate fuse box cover resellers! Presumably once you have a scanned data file of an original fuse box cover, you could 3D print off batches as required. Maybe also have several different relay location versions available.
Here is an ebay link to the US producer of the fuse box cover I purchased (which is still in transit):
https://www.ebay.com.au/itm/285621330503Andrew