Ventilation problem
 

Have a 2001 Bonne SE. Looking for cool air. When using either the air cond. or using outside air, the air temp out of all driver's side dash vents is a good bit warmer than the all dash vents on passenger side. It is manual air in the car. Heating part works good. Any ideas on what might be problem? Thanks!

zam, First I would recommend getting it scanned for any possible DTC's in the HVAC control module. You stated you have a manual HVAC system which seems strange that you're getting warmer air on driver side as opposed to passenger. There are three actuators on your HVAC housing: Air Temperature Actuator, Mode Actuator & Recirculation Actuator. It is possible that one of these is at fault or out of adjustment. Does the air distribution systen respond properly to mode changes?

Air dist. when called for is totally normal. I have had the car for nearly a year and it always worked this way. It seems stange to me that it could be an actuator out of wack affecting only one side of the car since it does not have dual air however It had been in a front end wild life collision before I got it and wind shield and hood and rad and condensor have been replaced. I'll get it checked and post reply. Thanks!

Yes, I agree completely. The HVAC housing has two main outlet ducts, the left supplies driver side air distribution, the right supplies passenger side air distribution even with manual HVAC. The actuators should affect both driver & passenger distrubution & temperature equally. I'm wondering if there is a door that is split on a common shaft & the driver side is not operating. I'm researching the FSM. You can access HVAC housing (blower motor & actuators) by removing the glove compartment and the passenger hush panel to have a look at things.

Won't have time next couple of days to pull things apart to check it out. I'm betting though that you've hit the nail on the head. Was looking at my owners manual today and it refers to the dual air system as having independant temp. controls for left and right but not independant fan speed. I'm betting GM uses the same HVAC housing and doors in both systems and simply adds an additional actuator for the dual air system. Must be a split door system to control temp. and the one will be either stuck, or spinning on the shaft. Will keep you posted. Thanks!

A couple of months ago I asked for help with ventilation problems on 2001 Bonneville where drivers' side air was much warmer than passenger side air on air conditioning and outside air modes. I had the complete dash dissasembled and found all actuators working normally and although it does not have dual zone air it does have the split door for it, but that is also all working fine. However the mechanic did find that the driver's side of the evaporator core was mostly plugged with dust and the like but only the driver's side portion(very strange)! He flushed and cleaned it as well as he could and presto we now have cold air coming out of the driver's side vents as well with a diferential of 6 degrees. Dealer did not mention that the plugged side was oilly(core leak). I presume not as then replacement would have been necessary. The car has a spot for a cabin air filter although there is none in there. He felt it was not the reason for the core plugging and would only install one for winter months. All this for only $750.00. That hurt but at least its working.

Wow......... John, that's a lot of loot. Glad to hear you got the problem resolved though. Thanks for the feedback also, it is vital information for other members that may have similar ventilation problems. ;)

Re: Ventilation problem
 

Is the air condition fully charged? Someone, somewhere posted that a low charge had caused theirs to be colder at one side of the evaporator and that air from that side predominately went to the passenger vent side of the box. So the passenger air was colder than the driver's side. They claimed they had the charge checked and topped off and everything was back to normal.

Not sure if I'm the poster imidazol is speaking of, but I'll relate. I had a very similar problem, although my 2000 SE has the dual AC controls. Mine was blowing just regular air out the driver's side and pretty cool air out the passenger side.

I discovered that when the system is low on coolant the the system defaults to blowing cool only to the passenger side, sounded a bit incredulous, but had it checked out at my local mechanic and sure enough it had a leak at the rear of the compressor.

Changed the compressor, recharged the system and all works great. I might add that the cost at my local guy's shop was HALF of the dealership I've always dealt with.

be careful with terms, some people might be confused, do you mean coolant/antifreeze? or refrigerant?

i am assuming refrigerant 134a