Heater and AC stop blowing

[markielowski]

Hello everybody. This is my first time posting here so please forgive anything dumb that I do. I am no mechanic but have a basic understanding of how car things should work and I know that the way my heater works on my 94 Q45 isnt right. I had the blower motor replaced once because it burnt out. I first noticed a problem on my five hour trips from college to home in the dead of bitter Ohio winters. Heat works great for probably 2 hours, blowing hot air, keeping my windows defrosted, etc. etc, but after that, the air coming out of the vents is less and less til nothing comes out. I can still hear the blower motor running full blast, but nothing is coming out on any setting, no defrost, no vents, no feet, nadda, which as you can imagine is horrible in 10 degree weather for 2 hours. I am hoping I can get this figured out before winter rolls back around. It used to only be the heater too, but today the air conditioning did something similar, I had it set to about 69 or 70 degrees on auto and went to turn it down to 65 to get some more cold air, The fan went up to full blast but there was barely any air coming out of the vents. Ive taken it to my mechanic while it was doing it once and they didn't even think there was anything wrong with it. Could someone please help me? I would ideally like a specific problem, or at least an idea so I can tell the mechanic what they should be looking for. Any help is appreciated. Thank you so much

[Q45tech]

94-96 Q45 have a plastic dowl [hinge] on the air mix door that breaks and needs to be replaced, common problem.The rub is removing everything to get to it can take all day by an expert.

Some members have developed a method to repair the hinge cutting time in half or more. Unlikely a business will do it the easy way because of warranty they usually give on their work.

Some one will post links.Be sure to download FSM for your Q45.

[markielowski]

I was reading in the service manual about the Heating/Cooling Unit and saw something about freeze up. Could this have anything to do with my problem? It does seem like a very gradual decrease in air flow like something is freezing over, rather than a sudden stop or like a door shutting. I have also noticed under the hood a lot of ice and frost build up on some of the copper looking pipes near the blower motor/ air conditioning stuff. Is this normal?

[Q45tech]

The HVAC assumes that the air flow is within specifications. Consider that the vent temperature can change 10degrees F from minimal fan speeed to max fan speed.

Without the air flow the system quickly freezes over!

One usually relies on the wisdom of those who have dealt with identical problems for the past 10-19.5 years.

Nothing new has occurred on 90-95 Q45 that was not known back in 2002.

At dealerships they see everything in the interval of brand new to 7 years because there are always a few early atypical failures.

I've even seen Q engines fail after 3 years of extremely bad oil change habits, same with putting ATF/PS in brake system.

By 2000 the problem with the 1994 HVAC redesign [cheap plastic] was well known thru out the industry. Every dealership has seen at least 1-10 examples.

Heck T3 has done 13 different vehicles in the past 9 years. I would extrapolate that at least 500 have been repaired in US............that's a 2-3% failure rate.....................everyone of which occured after the 4 year warranty was up!

[markielowski]

Well, after searching for a few minutes I found that post you mentioned about repairing the air mix door. I think Ill go ahead and see if thats the problem.

Thanks for your help

EDITJust got back, pulled the dash and radio out and saw the little plastic arm. It wasn't broken. I watched as it moved back and forth as I switched from hot to cold air. It was moving the door fine.Any other ideas?
Modified by markielowski at 10:35 AM 9/29/2009

[Q45tech]

There are 3 different position doors be sure to check them all.. Just because it appears to move from outside doesn't mean it moves inside.The shaft can break at different locations.

[markielowski]

cripes. What I did is just about the limit of what Im comfortable with as far as taking it apart. Looks like I'm gonna have to take this into a shop specializing in this sort of thing. Is there anything specific i should tell the mechanic to look for besides the air mix door? Or you think he'll be able to diagnose this himself? Hopefully Ill get someone whos worked with a q before. I'm really afraid to take it to a dealer because of the price to fix this. If it takes an expert a full day, I dont even want to think of how much itll cost.

On a related note, anyone know a mechanic familiar with q's in southeast Ohio/WV area?

[1996QShip]

this almost sounds like my issue... where do I find this link?