Intermittant Fault - Battery Light Comes On When Brake Pedal Pressed

[xeon123]

I am the owner of a 1.4i citroen zx from 1995 (no aircon). Until recently it has never given much trouble.

 

Now sometimes when I press the brake pedal the battery light comes on. This leads to ancillary power going off (like car battery, electric windows etc) but the car still drives ok - presumeably on battery power.

 

The problem is "random" and sometimes occurs for a few minutes without having to press the brake pedal to provoke it. Driving on bumpy road sometimes seems to fix it though.

 

Sometimes when the problem is ongoing I can hear a kind of electrical buzzing noise which seems to be coming from under the dashboard somewhere beneath the steering wheel. Haven't been able to pinpoint exactly or make the problem go away by shaking on the wiring.

 

I suspect that the problem is due to an electrical short in the brake light or related circuit (when the problem is active taking out the fuse "fixes" it and puting the fuse back triggers it again). Maybe I need to fit a new brake light switch and see if the problem goes away.

 

As the problem is random and never lasts more than a few minutes I am having trouble tracking it down.

 

Maybe a faulty brake light switch which sometimes "shorts to ground"? Anyone any ideas on best way to proceed and what could be the problem...

[techbod]

a buzz means a short and the relay could be the fault, as it doesn't last long? do you have air con

 

last post till tomorrow gnite all

[xeon123]

Thanks for the suggestion - I will have a look. Another idea I got from looking at this forum would be to check the brake lights in case they are double filament bulbs and maybe there is an intermittent fault with one filament touching another one. I don't have air conditioning

[kfk]

might be worth checking to see if the wiring harness is rubbing on the steering column.

[xeon123]

might be worth checking to see if the wiring harness is rubbing on the steering column.

Taking into account the two above suggestions (short + wiring harness rubbing) I had a look at the wiring under the steering column to see if I could find any wires rubbing off any metal parts. I quickly found that one set of wires was rubbing off one of the metal supports of the panelling. This metal support turns out to have a very sharp edge and indeed had cut away through the insulation of a rather thick looking wire. I would say that the metal and the wire were only barely making contact for the moment as the nick in the insulation was still quite small (but through to the metal underneath all right). I put some insulation round the affected wire and pushed the harness out of the way of the sharp edge. Problem has not reoccurred since (in 4 weeks)!

 

Thanks for all your suggestions

:P

[kfk]

Glad to see this problem was resolved - its appreciated you came back to tell us.