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HVAC Selector issue

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Old 05-17-2010, 12:50 PM
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Question HVAC Selector issue

I posted this in the general repair section but no real hits.

Posting it here since its dealing with a Trans Am.

It's my 2002 T/A, 42k on the clock.

What is happening is when I want to run either A/C or Heat, The part in the dash that selects the vents have stopped working where I am getting air on my feet and up through the defrost, Nothing from the 5 dash vents in front of me.

Has anyone experienced this, and do they have an Idea on where to start. I am more then capable of tearing the car apart. But I want to know where to start. I fear it may even be a resistor issue or something in the switch.
Old 05-18-2010, 10:04 AM
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That "switch" isn't really a switch at all, it's a vacuum porting valve. Start by looking on the back of the intake. You should see a vacuum hose heading into the body. Make sure this hose is indeed connected to vacuum. Also, inside the car there is I believe a "T" that is known for breaking. It's on the pass. side, I think above the kick panel.
Old 05-19-2010, 08:18 AM
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Originally Posted by fleetmgr
That "switch" isn't really a switch at all, it's a vacuum porting valve. Start by looking on the back of the intake. You should see a vacuum hose heading into the body. Make sure this hose is indeed connected to vacuum. Also, inside the car there is I believe a "T" that is known for breaking. It's on the pass. side, I think above the kick panel.
Yea, I do know that its vaccume operated and its good to hear I am not wrong.

I did swap intakes this winter and I suspect this may be the cause for concern. I will check the kick panel 1st and if thats fine. Then its off the hunt down that vaccume leak. I do hope I do not have to pull that intake again. I am 3-0 with out breaking the oil pressure sensor. DO I want to try for 4-0???

The main vac line that goes to the booster is fine but there is a smaller one and I think that may have slipped off. Which would make sense. As I think about it now.

I really appreciate the heads up.
Old 05-22-2010, 07:47 AM
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I had this issue with my car,a 2001 ws6 trans am. There is a check valve on the passenger side by the computer.I read on here that sometimes the plastic t will break.There are 3 vaacum lines running to it,I disconnected the hoses and found that the check valve in the t was clogged. I squirted some electrical parts cleaner in it and blew it out until it was cleared out,reinstalled and everything works fine.I wish I would of tried that first as I bought a new hvac control first.hope this can help someone out.
Old 07-03-2010, 08:56 AM
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UPDATE!

I found my issue. The car ended up throwing up a lean band 1 & 2 code and that generally means MAF related, meaning unmetered air is coming in. I had recently (winter) swapped out my FAST 90/90 set up to go back to a LS6 set up and a P&P TB.

I had NO Irractic idle or nothing to say UNMETERED AIR!

Ok wel I felt back in the intake and felt on the "T" style vaccume line that I was missing one connection. I could not though find the other end.

Welp I pulled the intake in a record 30-40 Minutes and I found what happend, the hard vaccume line that goes into the harness and into the dash was pinched inbetween the intake and cyl heads. It shut off the connection and I had a leak probably in the last cyl and "T" Fitting. I snipped it off, went to Autozone for a 89 Cent of rubber line and slipped her on both ways, put her back together and the VENTS WORK MINT!!!

Hard air is blowing, I have A/C and doing nice, and the car idles better so there must have been a little difference. I cleared the codes and its off to drive.



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