Technical Instrument panel faulty after flat battery

[trekkingnut]

Another issue with the Doblo camper after battery went flat. I noticed backlight flickering which was odd as ignition/lighting was off. Tried to start and was dead so disconnected battery earth and connected CTEK charger. After 3 hours charger had got very hot and charge bar was still on same level so I disconnected it and turned ignition on but no display (odometer) and only engine light, brake and airbag lights came on. I turned on radio and that was fine then the external lights and they came on but no backlighting on instrument cluster either so think something inside it has died perhaps? - checked all fuses relating to cluster including the big ones in engine bay and all are ok.

Sounds like an expensive fix but hoping someone has had similar issue to me and sorted theirs out - I will put a new battery in tomorrow but doubt the panel will work as radio was ok with old battery but will try and start it up. such a pain as MOT due soon too!

 

[AndyRKett]

What came first, the flat battery or the electrical problem that caused the flat battery?

The first thing to do is see what the battery is doing, if the voltage is too low such as having an internal short in one of the cells then this can throw up all sorts of errors and issues with low voltage

Basically you need a known good battery and start from there

 

[trekkingnut]

What came first, the flat battery or the electrical problem that caused the flat battery?

The first thing to do is see what the battery is doing, if the voltage is too low such as having an internal short in one of the cells then this can throw up all sorts of errors and issues with low voltage

Basically you need a known good battery and start from there

Thanks for reply and I agree, the battery needs replacing first but having had the same battery go flat a few times, the display always came up. It is different this time though as it would not charge but radio and external lights were working. The flickering of the backlighting was before I tried to start it and it continued after so I disconnected it. I cannot recall if odometer display worked before battery disconnected as flickering backlighting was where my attention was focussed. I will update tomorrow once new battery fitted and keep my fingers crossed.

 

[AndyRKett]

Thanks for reply and I agree, the battery needs replacing first but having had the same battery go flat a few times, the display always came up. It is different this time though as it would not charge but radio and external lights were working. The flickering of the backlighting was before I tried to start it and it continued after so I disconnected it. I cannot recall if odometer display worked before battery disconnected as flickering backlighting was where my attention was focussed. I will update tomorrow once new battery fitted and keep my fingers crossed.

Obviously lights and and the radio may be ok operating below 12v, but circuits like the body computer will switch the voltage down to 5v for their internal circuits and therefore if there is say 10v then that 5v may become less than 3v and cause all sorts of problems on those lower power circuits.

This is not a definite but you need a good battery to test it otherwise.

 

[trekkingnut]

Hi, Many thanks for a detailed and very informative reply and answering the puzzle because battery been flat 3 times before plus previous owner pancaked it as not used for 4 months so I knew it was weakened but generally been starting ok if used every few days so it made no sense what was happening. Obviously my first port of call was to get new battery whatever the cause but I got the garage to test old one out of interest and they reckoned it was weak but taking a charge (though it tailed off after a few minutes). However, I have fitted the new battery and voila all ok again thankfully so I have learnt something there as it has never happened ever before in all my years of motoring and many dead and even faulty batteries!

Your explanation is excellent and lifts the fog regarding what must have happened. I reckoned battery current must have been down as it is not always down to just volts. I was getting 12.4v on meter though and new battery is only 12.55v at the moment!