2007 XJR security alarm sets, chirps everything ok. Within a few hours goes off. reset and a few hours goes off again. Happened many times, different areas, garages etc.

 

It is usually the hood ajar sensor try bridging it with wire or replace it.

It is at the front of the engine compartment under the plastic cross piece.

 

Is it the switch in the middle. 4 inches or so behind latch. I shorted and get the error bonnet open?

 

Should you be able to Ohm it to see if works??????

 

On the occassion - is there a way to permanently disable the alarm? Or at least the audible part? I haven't found anything about it.

 

you have to disconnect the wire plug from the switch and jump the wire plug. tape out of the way.

 

If its not that, it's probably the trunk release button (in the trunk lid), easy and pretty cheap. Mine failed and kept telling the alarm that the trunk was open. The hood switch is more common though, and ya, it's best to just bypass it with a paperclip.

 

Is the switch in middle about 4 inches behind latch when I bypass the airbag light is on. cannot find another switch

 

Yes you have the right switch. I has just two wires, the black one to earth.
The solution must be to join the two wire together, which means it is closed permamently.
It must be some form of proximity switch which senses when the hood is
properly shut.
If you are having problems maybe set it nearer to the hood ie higher or replace switch?

 

When I bridged that switch the airbag on dash lights????

 

Goya I think I have got my wires crossed!

There is a hood switch under one of the latches.

There are two latches for the hood, one of them has a switch right underneath it. Look for two wires leading to it on one side.

Remove metal cover to access it.

Often people oil the latch which gets onto switch underneath.

Sorry for mix up