A/C dripping inside and outside of truck

JT78681 · June 1, 2018

A few weeks ago my truck began leaking water (not coolant) underneath the dashboard on the passenger side. I have exhausted myself researching what the issue could be and have tried all methods suggested to unclog the drain pipe if it was indeed clogged. I even purchased a new L shaped drain tube and installed it. The a/c blows cold and works fine it just leaks like crazy inside and out. I understand it is supposed to drip on the outside, but not the inside too and not at the rate it is dripping at. I am so hard headed that I refuse to pay the dealership god knows how much to fix this because in my mind this has to be something silly that I should be able to tackle. I would really appreciate anyone's thoughts or guidance as I am tired of rolling around with my carpet peeled back and a towel under the dash to soak up the water that is dripping. My truck is a 2011 GMC Sierra!

Edited June 1, 2018 by JT78681

JT78681 · June 1, 2018

Second picture you can see me pointing to the water drip when my truck has actually been off for hours. When it is on though and the a/c is running this drip is pretty darn steady at times.

Supreme Pizza · June 1, 2018

Like you, I never go to the dealer wither. I have seen problems like this before. Sometimes the seals/gaskets in the box dry out/shrink/crack/fail, and the water escapes before it exits through the drain tube. You may be able to use "gasket maker" to re-seal the box. It doesn't sound like your windshield seal is leaking, but that is another common cause. I have also seen blower air intake design flaws with TSB's.

Try this type of thing:

(I know, its an air filter box in the pic, but you get the idea)

JT78681 · June 1, 2018

Okay I can try this, but I have had no luck finding an article on how to remove the HVAC box. I have a feeling it could be quite the task to do. I am willing to try though whatever it takes to fix this because it is driving me crazy...

Supreme Pizza · June 1, 2018

A Chilton repair manual will have detailed instructions. They are available at most auto parts stores for about $25. Hayes will work too, but its not as complete (even though they are made by the same company).

I don't think you need to disassemble the box. Just find where the water is coming out and hit it with some sealer.

You can also look online for parts diagrams or exploded views.

Google your rig with the words :

"Parts fiche"

If you really cant find anything online, go to the dealer parts counter and tell them you want to buy parts from them, but you need to take it apart first to see whats broken, and ask them to print out the diagrams and or instructions. If they think they are going to make a sale, they will hook you up. Maybe its kind of sleazy to do this, but hey - the dealer is supposed to help out the customers out - not just try to bleed them dry.

Supreme Pizza · June 1, 2018

Example of an exploded view / parts fiche:

Supreme Pizza · June 1, 2018

If you really get desperate, you could drill a hole in the lowest part of the HVAC box, and thread a fitting into it. Then connect a tube to that, and then run the tube through a small hole in the floor, near the firewall.

Drill 2 holes, 1 piece of tube, and a fitting. Problem solved.

Colossus · June 1, 2018

^{off topic, but what did you do to your headlights? They look a bit different vs the factory look. I like.}

Supreme Pizza · June 1, 2018

I assume that you already tried blowing compressed air up your OEM A/C drain tube.

JT78681 · June 1, 2018

53 minutes ago, starman8tdc said:

I assume that you already tried blowing compressed air up your OEM A/C drain tube.

First off, thank you for the replies trying to help I really appreciate it! I swear ever since I paid off my truck back in November of course things start breaking. First my motor mounts which my brother and I replaced and now this....

I have tried shop vacuuming the hole, spray compressed air up there, poking the hole (that didn't sound right). Oh and I also just ran to Home Depot on my lunch break and picked up some coil cleaner. I dropped my blower motor and sprayed that stuff all in the vent that leads to where the coils are. We will see if that does anything. If it doesn't then I might just need to pick-up a manual from the parts store.

JT78681 · June 1, 2018

1 hour ago, Colossus said:

^{off topic, but what did you do to your headlights? They look a bit different vs the factory look. I like.}

I picked them up online. I believe these are it in the link below. If you decide to replace yours just remember to seal the housing to the lens up with silicone because they do a crap job on some of these after market headlight assemblies and condensation will get trapped inside and they will fog up.

https://www.ebay.com/itm/2007-2013-GMC-Sierra-1500-07-14-2500HD-3500HD-Black-Headlights-Replacement-Lamps/173088169508?hash=item284cdbde24:g:e-wAAOSwDApaX6N6