I have a 2007 LR3 SE and the horn stopped working. I believe the cause of it was that the hood sensor went bad and it kept making my alarm go off. I ended up replacing the hood sensor but now I need to fix the horn. I went to my autoshop today and they noted, "Fuse relay OK. Main horn relay built into fuse box assembly. Need time to disassemble and try to bypass." I don't really want them to bypass the factory system, so I'm looking for a fix. Anyone?

 

sure the fuses and relays are ok so far. and the main relay is "built into" the fuse box,

but if someone takes 12 volt power and hooks it direct to the horn, does it work? because the horn itself could be faulty while the relay is ok.

think of it this way: a light stops working in your house. do you check the bulb first or the breaker panel?

check the power at the connector for the horn with a test light, if that works then power is making it all the way but the horn (or the wires coming from it) are faulty. then test the horn it self with jumper wires and see if it works.

relays are not really "built in". that implies that it cannot be removed easily, but relays should just unplug from whatever block they are installed in. Your shop should have performed the tests I described and THEN ended up where they are now. but even so, there should be no reason to "BYPASS" anything. Perhaps they should provide a very clear description of what they are "bypassing"

 

While I wouldn't put it past LR to somehow integrate the horn into the CAN buss or some other nonsense, it should in all actuality be a very simple circuit as described above. Just use a meter or test light to see if you're getting 12v to the horn itself. If not, you need to check the fuse and relay. If yes, you need to check the horn itself by jumpering it straight to 12v. It's about the as simple a circuit as you'll find on a car so I'm not sure what the shop is worried about.