came back today from shopping with my horn going full blast dunno if thats part of the alarm or wot disconnected the battery left it for 15 mins then came back put the battery connector back on and fired up the car and then after 5 mins the horn/alarm starts again but the engine aint stopped so guessing its not the immobilizer/alarm thats the problem now, as i thought the engine would of cut out, any1 any ideas or had something similar :angry:

Horn issue`s like this are usually a cable fault, the cable from the horn push button is a switched earth to the horn relay, if this cable becomes earthed somewhere the horn relay will sound even with the ignition off.

 

Most times it is easier to replace the offending cable rather than spend hours looking for the fault. In the meantime just remove the horn fuse located in the relay box under the bonnet on the passenger side inner wing, it is marked on the lid which one it is and should be a red 10amp one.

 

Jeff TT