citroen berlingo electrical problem?

[wullawulla54]

I have a citroen berlingo 1.9 diesel 54 reg. I had it in for its M O T yesterday and it failed on the horn not working. I had it in to the mechanic today who spent all day on it and couldnt find the problem. He put the diagnostic machine on it and there was no power to this machine even. The stupid thing is that when the key is taken completely out the horn then works. (the horn is in the middle of the steering wheel) Put the key back in and it doesnt. If you press the horn when the key is completely out and keep it pressed so that its working when you put the key in it still works until you give it one turn on the ignition. The mechanic told me to go a scrap yard for a new/used fuse box which i did but the guy told me that I would new a complete new kit and he didnt have one in stock anyway. Please can somebody help as I have only got 5 working days left to fix the problem. Apparently the horn and the diagnostic plug is all connected according to the haynes manual.

 

[Jakub]

If Your indicators go on and off and You suffering from airbag errors you might try connectors underneath airbag and light-switch module. But start with fuses, relays and cable connections - maybe connection with chassis (GND) is broken somewhere.

 

[BWG1]

to be quite honest you need an auto electrician, all the playing around with the electrics will not solve this and the wiring on some models was a joke as what is now known as multiplex wiring meaning some of the electrics works more than one part of the system. the electrics on mine drove me nuts. hope maybe somebody might have an answer for you.