L322 Alarm going off for no reason

2 days in and the fun has started.

The alarm keep going off for no reason and the key fobs don't have any impact. I've tried opening car with keys and no lights come on inside, also unable to turn the key to start the car.

Ideas and solutions welcomed, Sunday isn't the greatest of days to get any parts if required.

What year is the car? If an early 322 Does the red LED light up when you press the buttons on the fob?I take it both keys and fobs worked in the car when you purchased 2 days ago?
I would check the main battery under the hood to start with too.

Sounds like your battery has given up the ghost, first rule of fault finding on a range rover start with a good known battery.

Key Fobs were working on Thursday when I collected car and they do flash red. I will start with the battery. Is there also a known problem around the bonnet sensor, if so, what part number would this be?

Keep the help coming.

What kind of battery should I be looking for?

The biggest amp hour highest cold cranking amps you can physically fit in there, eg 120ah 1000cca
is yours a Vogue model as they should have the bigger battery, the battery should only just fit and we are talking mm`s clearance with the leads pulled out the way, if you fit a new one check the output of the alternator with a multi meter you should get around 14.9 volts at 2000rpm under full load, eg lights on full heater everything, hope that helps.

The car is a 2003 HSE

Anyone also know the part number for the bonnet sensor?

Once battery is sorted, Maybe try disconnecting the bonnet switch to rule it out if that would work?

Do the battery first, then look for other issues. The HSE isn't as greedy as the Vogue but no harm in still fitting the biggest she will take. Once the battery is fixed, if alarm still going off, search the forums for the microcat link that several have posted previously. Then you'll be able to find all the part numbers your heart and veh desire.

Hi, I had the same problem many years ago and it turned out to be the ecu in the A post (windscreen post/channel) on the passenger side. As well as the horn going off the air suspension wouldn't work and the car wouldn't start. Easy to find, take the trim off and the ecu is close to the floor. I think it controls the headlights or something. If it is like mine it will be full of water, it doesn't help as there is a lot of sound deadening material down there and acts like a sponge, dried it off with a hairdryer and all was ok. When refitting clip it up out of the way with tie wraps. Cheers Ian