Strange beeping noise
 

I have a 1998 b3000. I start it up and let it warm up for awhile to get the oil circulating. Than a strange beeping noise comes on. it will beep 5 or 6 times than stop for a sec than do it again another 2 times...same pattern. Than it will go off and come back again as i am driving the truck. Any ideas or suggestions would be greatly appreciated