Built in alarm/imobilizer question

[Matt Vee]

Hi, I have a problem........

Like a dipshit I left the key to my truck in the door last night and some fcker nicked it. I think they didn't bother nicking the truck because it was full of stinking rubbish I was going to take to the rubbish dump this am.

I have a spare key and also I dug out the key fob.

Here is the situation I find myself in.
The Key fob locks all the doors except the driver door. No problem as I have a key for that.
The barrel of my ignition is dodgy as in it's not really a lock anymore so I can press the key fob once and the doors lock except the drivers door get in and start the engine.
When I press the key fob once the doors lock (except the drivers door) and if I press it again the indicators all flash. All good.
When I get in I can start the truck, the indicators flash (like hazard lights) but there is no "alarm noise" so from this I have concluded that either the horns are meant to sound or someone has ripped out the alarm Noise maker at some point because it pissed them off maybe.
When I got insurance for my truck the person I spoke to said the truck was fitted with a thatcham approved alarm/imobilizer.
Is this correct?
If this is correct why is the imobilizer not operating?
Is it due to user error (i.e I'm an idiot) or do you suspect there is something up with the imobilzer (if it is fitted)
Thanks, I really need to get something sorted ASAP as I have a feeling the turd that nicked the key is just waiting for me to remove the rubbish from the truck before they make a move.

Also clearly I am an idiot because I left the keys in the door so please bare that in mind in your answers, you may have to explain it to me like I just landed from mars or something.

 

[Mick W]

Matt, as a temporary measure I'd stick an ignition isolating switch somewhere under the dash (that only you can find/access) until you can sort the alarm system out. At least the little f*kka that nicked the key shouldn't be able to nick the truck as well!

 

[Shayne]

That's likely a druggy or a kid who can't drive and wouldn't know what to do with a stolen car or it would be gone so like as not he hopes to return and steal things he can sell out of it .

If the fob works for 3 doors it should work for 4 , i'd disconnect the battery overnight and try with the fob in the morning , if it doesn't work correctly try holding down both lock and unlock buttons at the same time to resynch

 

[Matt Vee]

Thanks dudes

 

[AdventureWagon]

If not then maybe a wiring issue, the door to body wires will be quite tired after 20 years of door opening etc. You could always remove a critical component (e.g. igniter if it's a petrol, starter relay maybe) to hopefully hinder theft until you can change the locks.

 

[Matt Vee]

Got my keys back