C2 erratic / flickering electrics

[Arbuthnot]

Hi all,
A couple of months ago I picked up a 2007 1.1 petrol C2 for the missus, only about 45k on the clock and has done very little the last 2 years. Starts and drives quite well but the first time I took it out at night it seemed like the headlights were wavering a bit. This is the most modern car I've ever had so I wondered if it was self-adjusting lights or something but it's not. Even at idle with the headlights off you can see the backlit speedo faintly going dim a bit.

At first wondered if it was the alternator because the charging voltage seemed high and erratic but I realised it was the original 2007 battery so I changed that and it's OK. When driving the cigarette lighter socket will sometimes work, sometimes not, as well as one of the backlights for the heater control - it might just randomly start / stop working. The rear demister works, but the relay (?) keeps clicking from the glovebox. Then the central locking became temperamental; I checked and replaced the batteries in both fobs and it seemed OK for a week but then basically stopped working altogether. I looked up how to do a "BSI reset" from a post on here, had to try that 2 or 3 times then it worked fine again - for a week. Now no central locking, I have to use the button on the dash through the open driver's window then hit the window button and pull the key...

I've cleaned up the battery leads, looked for obvious damage in the fusebox, sprayed WD40 everywhere. Running short of ideas now, I really long for the days of fixing electrical problems with a bulb on a wire with a croc clip.... any advice welcome!

[Paul-R]

Do you have any idea how old the main car battery is?

[Arbuthnot]

Do you have any idea how old the main car battery is?

It was the original battery - date code on of 2007 - it was pretty stuffed. It's now got a brand-new good quality battery. The charging voltage is fine, but the flickery gremlins persist.

[wheeler]

What is your charging voltage with both no load & all loads switched on? Is there any difference if you measure this directly on the alternator positive terminal & alternator casing as the earth?
Next i would remove & clean main earth cable on gearbox & chassis.

As for the central locking, have you tried resyncing the remote? The best way i find is to sit in the car, switch the ignition on & repeatedly press the lock button on the remote for 10 seconds. Remove the key, open & close the drivers door then wait 30 seconds before trying the remote.

[Arbuthnot]

What is your charging voltage with both no load & all loads switched on? Is there any difference if you measure this directly on the alternator positive terminal & alternator casing as the earth?
Next i would remove & clean main earth cable on gearbox & chassis.

As for the central locking, have you tried resyncing the remote? The best way i find is to sit in the car, switch the ignition on & repeatedly press the lock button on the remote for 10 seconds. Remove the key, open & close the drivers door then wait 30 seconds before trying the remote.

Charging voltage is 14.6V with nothing on, about 14.3V with all the buttons pressed - that's measured through the cigarette socket and at the battery, admittedly, I'll double check it on the alternator when I get a chance. (I did get a local garage to check it when it had MOT recently and they thought the alternator was fine, but they are maybe more of a tyres and exhausts kind of place). I did try a quick test of a jump lead from the battery negative to the top of the engine to try and bypass the main earth cable, but I will also get in and check that.

As I said, I'd reset the BSI and resynced the remote(s) and it was fine for a bit, then intermittent, then dead. I had a feeling it was more like either a fault in the BSI or an electrical gremlin elsewhere that was making the BSI glitch, so a reset fixed it temporarily? But admittedly I don't have much experience with this type of system.

[ozvtr]

When driving the cigarette lighter socket will sometimes work, sometimes not,

Crap/rust on the center terminal. Scrape the center terminal with a screw driver to get a clean contact. Excess current draw from the actual lighter part or accessories can melt wires and burn out the contacts.

one of the backlights for the heater control - it might just randomly start / stop working.

These are incandescent lamps. Remove the radio and use a mirror to find the bulb holder on the back of the control panel. Replace the bulb.

Then the central locking became temperamental; I checked and replaced the batteries in both fobs and it seemed OK for a week but then basically stopped working altogether. I looked up how to do a "BSI reset" from a post on here, had to try that 2 or 3 times then it worked fine again - for a week. Now no central locking, I have to use the button on the dash through the open driver's window then hit the window button and pull the key...

Typical failure here is the relays in the BSI BUT the dash button is working so it's not that.
The receiver for the central locking is in the top of the COM2000 between the steering wheel and the instrument cluster. Try holding the plips there and see what happens.
Next failure mode is the buttons on the plips. But if neither plip works in open OR lock mode, That indicates a problem with the system in the car.
There is a locking mechanism at the back of the passenger door, near the striker, that will lock the passenger door. Use the key lock in the handle to lock the drivers door.

[Arbuthnot]

Thanks for the reply. Yeah, if it was one of the things cigarette socket / dash backlight / rear demister that was playing up it would obviously point to a local failure, but when it's all of them intermittently it makes me think it's something more fundamental. I agree the central locking relay must be OK as the dash button works, I've done the batteries in both fobs and reset the BSI and they work but again only for a while - it's as if something is scrambling the computer's brain. The weather has been horrendous here and the missus and I work fairly different shifts so I've not had much chance to look at it recently but I wonder if it isn't the main earth or the alternator.