[jimcol]

1retired06 gives some good advice. Past post have indicated the factory either over tightens the units compressing the gasket too much or under tightens them, both leading to leaks. Checking the drain holes in the A/C pan is also a good advice. Not hard for them to get blocked by leaves or other debris. Another common source for a leak over the bed is the OTA antennae. The boot covering the coax where it goes through the mount/roof gets pulled off. Couple of dabs of silicone caulk before putting the boot back in place generally fixes this issue.