I have a 1993 GMC suburban and the carpet in the rear cargo area gets wet when it rains. i was sitting in the rear when it was rainning 1 day and did not see any rain come in around the windows or seals around the doors. please help

Get your heater core checked. May be leaking.

Possibly from the windshield. Is there any rust around the windshield area? Check for debris in water drain outlets under the wiper arm cowling.

And where exactly is this rain coming from? The sun roof? The door seals? Seeping in down in the footwells (soggy carpet)?

Sometimes "rain" can be mistaken for A/C condensate that is not draining due to a plugged condensate drain. If your A/C is running and it's hot and humid out then you should see some water drips on the ground underneath the front area of the vehicle. Let it sit in one location for a few minutes after you come in from driving it. Let it sit for a few minutes with the engine and A/C running. Move the vehicle and look for the telltale wet spots from the condensate drain. If you don't see a wet spot then chances are the drain is plugged. The condensate will back up and drain inside the car ...typically in the passenger footwell and making the carpet wet.

The two most common causes are rain water leaking in or the ac drain being clogged up. I would vote for rain water if the entire carpet area is wet.
Could be coming in around the windshield, or one of the door gaskets.

does it have a sun roof and the drains are plugged up?

Just fixed the same issue on our 2004 Suburban. Turned out it was just that the drain for the rear A/C was clogged with dirt (located right behind right rear tire -- above the exhaust pipe). All it took was a paperclip, straightened out, poking gently in this narrow rubber ****... and the water came gushing out (floor was wet at the time). If you do it when the floor is dry, you would have to turn on the rear A/C for a while and make sure the condensate drips out of the drain.

Your ignition system cables, particularly the one from the coil, and maybe from the battery, are old and cracked. Replace them.

You'll have to pull up the carpeting, but it sounds like there is a hole in the body somewhere that needs to be sealed.
matt

Mother nature is too slow in finding leaks. Have someone small get in the trunk with a flashligh and watch as you run a hose over everything. LET THE PERSON OUT!

sounds like the air conditioning drain for condensation is plugged