Hi All from down under! Have just purchased a 1986 Mondial 3.2 and I’m slowly working through a list of issues that need sorting. Wondering if anyone has had to fix a weak sounding horn. Pressing the horn button requires firm pressure only to produce a muted, low tone and not very loud sound. Any ideas?
Probably the compressor for the air horns needs oil or something is loose. Most people do not realize the compressor has oil in it.
Clean the electric contacts and grounds from horn and screen washer pump. See if you have 12 V at these points fusebox : Without contact on : upper side fuse 9 /underside fuse 9. Take relais e out (3e little (brown) from the upper left) and see you have 12 V upper and right contact + X10 (second contact left side of upper right white plug with wires). Also some Volt (voltage drop from internal coil) lower relais contact and at X11 (first contact left side of upper right white plug with wires). This goes to steering then to ground. Put e relais back. When pushing on the horn you should have 12 V at U4 (4e contact counting from under, of the middle vertical white plug with wires on the left side). If there is a current drop you will found out where it is...contacts, layers fuseboard, horn pump or horn switch. Image Unavailable, Please Login Guido
All good suggestions here. A number of years back the horn was weak on my 328 or 355 (don't remember). I removed the horn relay, manually applied 12 volts to the relay coil contacts and then connected an ohmmeter to the closed contacts. I measured something like 2 or 3 ohms, if I recall. Way too much resistance. The internal relay contacts were probably damaged from pitting over time. Replaced the relay coil and all was good. I would start by connecting a voltmeter right on the horn compressor electrical terminals with the car idling. Have someone hold down the horn button. If you don't have good, strong voltage there I would work my way back toward the horn button itself although I would go right to the horn relay next since it's pretty easy to check. If you're not an electrical/electronics type I would buy a new relay and swap it out. If it fixes it, great. If not, put the old relay back in and you'll have a spare new relay on hand - never a bad thing. Then continue checking everything in between.
All good suggestions here. A number of years back the horn was weak on my 328 or 355 (don't remember). I removed the horn relay, manually applied 12 volts to the relay coil contacts and then connected an ohmmeter to the closed contacts. I measured something like 2 or 3 ohms, if I recall. Way too much resistance. The internal relay contacts were probably damaged from pitting over time. Replaced the relay coil and all was good. I would start by connecting a voltmeter right to the horn compressor electrical terminals with the car idling. Have someone hold down the horn button. If you don't have good, strong voltage there I would work my way back toward the horn button itself although I would go right to the horn relay next since it's pretty easy to check. If you're not an electrical/electronics type I would buy a new relay and swap it out. If it fixes it, great. If not, put the old relay back in and you'll have a spare new relay on hand - never a bad thing. Then continue checking everything in between. Alternatively, you could run a couple of (not too thin) wires from the car battery right to the horn compressor terminals. That would eliminate everything in between such as the horn button, fuse panel, relay, wiring, connectors etc. If the horn is still weak then it's likely the compressor is gummed-up inside, needs oil or new air hoses (leaking) or maybe all these.
