Hi, can anyone please help?Baldness is just round the corner from me pulling my hair out with this problem.
l have a 1996 Peugeot 806 2.0 SR it seems to have a mind of its own. sometimes you get in turn the key and no problem perfect starts and is ok. But more often than not you get in turn the key everything on the dash lights up ok and nothing not even the radio or blower, then you try again and you may be lucky and it starts or not. when it is in this stubborn mode all that can be heard is a buzz and a click from behind the glove-box. The battery has been replaced with new. please can anyone help? many thanks

This sounds very much like someone has not fitted the battery positive connection properly. Either that or another main feed wire has a problem (corrosion, pinched) but that is less likely.

l know this may sound daft, but u would not believe the weird problems l have seen on 806/C8 just from the battery terminal not beeing on right. Its also a nice easy cheap thing to check.

The other possibility is an internal BS l fault. The buzzing u can hear from behind the glovebox is the sound of rapidly switching relays within the BSI, this may be caused by an irregular power supply to them (battery positive terminal problem) or by a problem with power contacts within the BS l itself. To replace the BS l needs the specialist knowledge & diagnostic tools of a Peugeot dealer though, takes around an hour & the part costs approx. £200.

(but l bet its the battery terminal!)