AC Condensation Drain

I have a 2000 Bravada. AC works for about 30 minutes and then slowing looses its cooling ability. If I let it sit for a few days, it works again----for about 30 minutes.
Compressor cycles when its acting up, but not at the same rate as when its working.
I am wondering if the Drain tube is pluged up and its getting full of water??
Looked for the drain tube tonight and could not find it. Everything is such a tight fit back near the firewall that its hard to get in there and see anything. Took a mirror and flashlight and that still didn't let me discover the location of the drain.
Can someone give me a clue where the drain is on this car? Thx in advance for your help

I have a 2000 Bravada. AC works for about 30 minutes and then slowing looses its cooling ability. If I let it sit for a few days, it works again----for about 30 minutes.
Compressor cycles when its acting up, but not at the same rate as when its working.
I am wondering if the Drain tube is pluged up and its getting full of water??
Looked for the drain tube tonight and could not find it. Everything is such a tight fit back near the firewall that its hard to get in there and see anything. Took a mirror and flashlight and that still didn't let me discover the location of the drain.
Can someone give me a clue where the drain is on this car? Thx in advance for your help

If the evaporator core is in underhood area there ia olly aslot righ under it for drain.

Do you ever see water running out on ground/payment?

Ac ever been re-charged?