My Hazards keep going off??

I have a W reg Clio that's had a secondary immobiliser fitted. Anyway the secondary immobiliser has been disconnected from the relay so should not work. What's happening is that sometimes if I'm driving or my car is stationary my hazards lights come on for about 20 seconds at a time then go off. It's as if the car alarm is going off with no noise then switches itself off!
Anyone ever had this problem?.

Thanks.