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Automotive Onboard Display

Thread starter #1
Hi Everyone

Can someone out there give me some help, I've got a Vauxhall Omega 2.5 Turbo Diesel year 2000, the car had not been used for about two weeks and when I came to start it up, the battery was dead ie. not enough energy to crank the engine over.

It was put on charge and sure enough the car started, this was when I noticed something was not right because when the ignition key was taken out the on-board display or computer if you like, was not turning off as it should do, it was still displaying the time of day and outside temperature even though it should have been off.

I'm not into electronics and wondered if anyone can suggest some simple checks I could do to find out what's going on, I'm only guessing here but could it be a fault developed in the car ignition switch.
I'm assuming the reason for the flat battery is because the display was stuck on, at the moment the only way I can get it to go off is by disconnecting the battery negative.

Thanks to anyone who can shed some light.
 

rjenkinsgb

Active Member
#2
It could be a welded relay.
The ignition switch does not usually control power circuits directly, it operates relays which in turn switch the higher currents.

If a relay contact sticks or welds, power will stay on despite the ignition being off.

Try unplugging relays one at a time to see of one switches off the dashboard power? Replace any that do not before trying another.
Some are probably in or near the one of the fuseboxes.
 
Last edited:
Thread starter #3
Hello rjenkinsgb

Thank you for your quick reply, I will most certainly give that a try, just a thought but am I right in assuming it would be nothing to do with fuses so I can dismiss checking those.
I guess fuses are either working or blown end of story?
 
#4
A relay is a possibility. The car battery is dead because its cold and you did not start the car for 2 weeks. Its possible that there is a fault in the development there are always faults, but I don't believe this one. The best option is to find a car the same model as yours and check. A second option is to check a similar car with similar functionality, but I don't know how accurate the check will be if the other car does not have the problem.

On "Ignition ON" most electronics are on. On ignition off, most electronics should be off. The alarm system is always on and maybe others as well.
 

rjenkinsgb

Active Member
#5
Fuses are unlikely to be a problem, unless some other module is getting messed up and causing problems on a data bus.

Thinking of that - just try disconnecting the battery for at least one hour then try and reconnect "cleanly", ie. in one go with no making and breaking the contact.

It's just possible something has crashed in one of the electronics modules and brief disconnections are not allowing it's internal backup to drain and allow a proper reset.

If the battery has already been disconnected for long periods and reconnected while in a fully charged state, it's not that particular problem.
 

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