AC Vents Issue

[Lurayfarmer]

Today I finished installing a new radio and AC hoses. I opted to delete the long second AC hose to the center vent using a plug set from a vendor. A single hose to that vent seemed adequate. I cranked up the AC - and found nothing at all coming from the center vent. The hose is on tight, and when I lift off the plastic nozzle from the main manifold there is cold air coming out.

My guess is that the double hose was used when some GM engineer discovered the same problem using a single smaller diameter hose for the center vent. Air coming up from the blower looks for the easiest exit, and that's the main AC vents which have a larger diameter.

Anyone else delete the second hose to the center vent and get this issue?

[chewychevy67]

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[cdowns]

have you checked the black box on the floor to see if the flapper valve works

[Lurayfarmer]

I'll check that tomorrow.

[Already Gone]

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[NTIMID8R]

I did the hose delete and plug when I replaced all the hoses on mine. I also removed the diverter box that directs the air and found the rubber damper was broken. I used two small metal plates (one on each side of the damper) and JB Weld to repair it. Worked like a charm. I will say that the volume of air from the center vent is not what I expected it to be but I can live with it for now. I have seen a replacement center vent that only has one hose port and is made with more of a curve so the air comes out less restricted but don't remember which vendor had it. Good luck with yours.

[Lurayfarmer]

Very helpful. I had the diverter box off while making other repairs (resistor replacement) and its internals looked OK. Overall flow to the AC vents is excellent. But I also used a slightly larger ID hose for the side vents to overcome the "hose too small" issue. This may cause too little flow resistance. I'm going to try inserting a partial baffle in the passenger side AC vent to creat some backpressure. That would be a simple task. The other center vent you mentioned might also be an improvement -- but I'm not going back in there again!

[Katrina/10]

Originally Posted by Lurayfarmer

Today I finished installing a new radio and AC hoses. I opted to delete the long second AC hose to the center vent using a plug set from a vendor. A single hose to that vent seemed adequate. I cranked up the AC - and found nothing at all coming from the center vent. The hose is on tight, and when I lift off the plastic nozzle from the main manifold there is cold air coming out.

My guess is that the double hose was used when some GM engineer discovered the same problem using a single smaller diameter hose for the center vent. Air coming up from the blower looks for the easiest exit, and that's the main AC vents which have a larger diameter.

Anyone else delete the second hose to the center vent and get this issue?

I also used a single hose fed from the passenger side to the center vent. I got good air flow out of the center vent, but since it is fed only from one side, it blows off center, towards the driver. I didn't mind extra air on me. I used all standard size replacement hoses. I think you must have some kind of restriction in your center vent feed hose.

[Lurayfarmer]

Ok, this was a knucklehead incident. One person responding suggested the AC hose might be blocked. I pulled it off-nope, fine. Then it dawned on me. I inserted the cap on the center vent before installing it. The center vent housing is kind of tricky - you can actually put it in upside down. While installing it, I needed to flip it to get it in correctly. This put the cap on the other end! Yikes. Anyway, a word to the wise. Don't do this!

Thanks for all the replies.

[Katrina/10]

Well, that explains it! Glad you figured it out.

[lawest]

Brothers has the single hose center vent housings. http://www.brotherstrucks.com/prodin...number=CVUG072

[Lurayfarmer]

That would be great, thanks for pointing it out. The only bad part is that I'd have to get in there again, as it attaches from the back. Maybe when the weather gets hot I'll be inclined to take it on.

[Andy4639]

Originally Posted by Lurayfarmer

Ok, this was a knucklehead incident. One person responding suggested the AC hose might be blocked. I pulled it off-nope, fine. Then it dawned on me. I inserted the cap on the center vent before installing it. The center vent housing is kind of tricky - you can actually put it in upside down. While installing it, I needed to flip it to get it in correctly. This put the cap on the other end! Yikes. Anyway, a word to the wise. Don't do this!

Thanks for all the replies.

That's a good one man!
We've all done things like that before.
We just need to remember to learn from it the next time.

I also blocked my one drivers side center opening and mine blows good all over.

[davepl]

I was sure there was a year or a scenario in which the factory did this themselves, as I've seen it, but can't put my finger on where or when.

Technically I still think the dual pipe might flow more, but it's all one fan so I wouldn't assume anything.

[Andy4639]

Thinking out loud here so:

The system was designed for 4 outlets drivers side, passenger side and the 2 center ones into the single vent.

So if you take the hose lose it should be the same amount of air blowing but since the one line is blocked off, it's blowing the same amount of air through less space. That in return makes it feel stronger to the person sitting in the truck.