'03 Disco. No horn. SRS light on. Also, no Bentley manual?!

OK I did a search and although I did figure out a lot about what the problem may be, I was looking for a little more insight than I could find.  I was a member on bimmerforums when I had my BMW for years, so I know how the whole "search first" thing works....  I searched.

Anyway, I recently bought an '03 Disco SE.  The battery was dead, and I had it replaced.  I thought that may be the reason for the SRS light, but the horn also doesn't work.  Now, I wouldn't think that it would just need a clearing of the SRS/ECU at a dealer if the horn's not working....  That points me to the horn coil, coupler, or some sort of electrical open in that circuit.  The fuse is fine.

Now, I can't find for the life of me a Bentley, Chilton's, or Haynes manual for this thing.  And I'm not exactly sure I want to just go tearing things apart without knowing what I'm looking for and exactly what I'm doing.  I've rewired and rebuilt my '68 GTO myself, and I did everything myself on my '98 328i, so I'd say I'm a pretty capable DIY guy.

Does anyone know where to get a service manual?  Or do I just look for one for the '02 (which I can find)?  And I'm sure someone has gone through this before, seeing as how it's an extremely common problem, so I was wondering if there was any insight out there that could be pointed in my direction....

Also, is there a better place to go in the future for DIY advice?  I really hate going to the dealer, especially in San Diego, if I don't absolutely have to.

Thanks for any and all support.

First of all, the SRS light will need to be cleared by a lap top type scanner that can access and clear that code that was most likely set due to the battery voltage.
The horn is a completely different issue, I would suggest checking your fuse for that issue.

Will the airbag still deploy with the SRS warning light on?  I've found conflicting opinions on here...

Normally no. The one positive thing is that it will not deploy when not needed, take that from nearly 30 years as a service manager.

My horn wasn't working and I found it was the fuse.  The rest I can't help with......