I have a 2007 SRT-6. The car locks fine and I get the 3 flashes when I test the system however when I'm in the car it sounds like the pump in the boot is going for quite a while after. Even though my car is still locking I'm concerned that the pump will be working more than it should due to perhaps a problem with the vacuum system. Lady owner, so any helpful suggestions welcome before I get ripped off by a garage ! thanks

 

The pump is quite quiet and I am wondering if it is actually the pump you are hearing. I would test the pump by listening for it with your head inside the trunk/boot area and locking and unlocking the car.

 

The noise comes from behind the drivers side in the trunk of the car and whirs for several seconds longer than normal

 

It is possible that there is a small leak in one of the hoses to one of the locks. The hose that passes through the rubber boot at the top of the hatch is one place that the hose breaks, when it breaks the pump runs longer than normal. Yours maybe running longer to get up to pressure due to a leak.
I take it you are in the UK and have a RHD car.

 

Yes it is a right hand drive, bought from the UK

 

Thank you, will have a look to see what I can find