UK Car Repair Questions? Ask a Mechanic for Answers ASAP
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Obviously I don't know your level of expertise in this field so I'll try and put it simply for you.
Ok. The best way to get the bonnet open without breaking a window of course is if you Jack up the car at the front and put it on stands for support. Then what you need to do is using a torch look up aS the front on the engine side of the radiator and see if you can see the locking mechanism. Then using a lever of some kind use this to lever at the release mechanism to the left or right I can't be too sure from memory. Once you get it popped you can then open the bonnet and get the battery changed and then unlock the car that way.
On another note, was the ignition lock changed at some point? If not maybe the lock is just seized from lack of use so you could also try spraying wd40 into the lock and then inserting the key and trying to free it up watching you don't break the key that is.
The safest way to open the bonnet if you don't trust the lock way though would be from underneath.
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