need help with climate controls
09-09-2007, 07:05 PM
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Car: 1989 Pontiac Trans Am GTA
need help with climate controls
Hi,
Before I start - yes, I've searched and read through the results.
I think my climate controls are only blowing through the defrost vents, but it also seems like they are blowing through the bottom vents too (so perhaps its stuck on bi-level?).
Either way - I checked all the vacuum lines on the interior of the car. They are all good, with no kinks/bends and they all connect to their diaphrams properly.
I know the purple line is the "input" line for the vacuum from the engine bay, and there is another grey one that connects to the same plug (I don't know what it's for). The side that connects with the purple line does suck air in, albeit not as much as I would expect it to. How hard should it be sucking?
I unplugged the vacuum lines from the climate control pod thing, and the purple lines ARE sucking air, but its quite weak.
What should my next step be? The climate controls don't change their behaviour when the vacuum lines are completely disconnected from the pod. Is the vacuum in the purple line perhaps not strong enough?
One more question - My AC doesn't seem to work, and I don't know if it is because I need a recharge or because it isn't going on. How can you tell if the compressor is on?
Before I start - yes, I've searched and read through the results.
I think my climate controls are only blowing through the defrost vents, but it also seems like they are blowing through the bottom vents too (so perhaps its stuck on bi-level?).
Either way - I checked all the vacuum lines on the interior of the car. They are all good, with no kinks/bends and they all connect to their diaphrams properly.
I know the purple line is the "input" line for the vacuum from the engine bay, and there is another grey one that connects to the same plug (I don't know what it's for). The side that connects with the purple line does suck air in, albeit not as much as I would expect it to. How hard should it be sucking?
I unplugged the vacuum lines from the climate control pod thing, and the purple lines ARE sucking air, but its quite weak.
What should my next step be? The climate controls don't change their behaviour when the vacuum lines are completely disconnected from the pod. Is the vacuum in the purple line perhaps not strong enough?
One more question - My AC doesn't seem to work, and I don't know if it is because I need a recharge or because it isn't going on. How can you tell if the compressor is on?
10-02-2007, 06:57 AM
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Re: need help with climate controls
The purple line should connect to a vacuum "accumulator" of some sort under the hood; I believe in your car, it's a sphere in the driver's side fender near the headlight. Somebody that knows that particular model of car, correct if I'm wrong.
It doesn't connect "directly", however; IIRC there's a line coming from the intake plenum that "supplies" vacuum, which goes to a check valve (so that once the vacuum has "filled" the line on the opposite side, it can't go back to the engine); then a "T"; and one side of the "T" goes to the accumulator, and one goes to the purple line.
Probably easiest to trace it all backwards. The purple line comes through the firewall near the heater core, since it's part of the separate, unitized HVAC harness. Find the "T", see how much vacuum is there; trace the line to the accumulator, make sure nothing is broken; etc.
The gray one would be for the heater control valve line, which also goes back out under the hood. IIRC the various ones inside the car are red, yellow, and blue.
It doesn't connect "directly", however; IIRC there's a line coming from the intake plenum that "supplies" vacuum, which goes to a check valve (so that once the vacuum has "filled" the line on the opposite side, it can't go back to the engine); then a "T"; and one side of the "T" goes to the accumulator, and one goes to the purple line.
Probably easiest to trace it all backwards. The purple line comes through the firewall near the heater core, since it's part of the separate, unitized HVAC harness. Find the "T", see how much vacuum is there; trace the line to the accumulator, make sure nothing is broken; etc.
The gray one would be for the heater control valve line, which also goes back out under the hood. IIRC the various ones inside the car are red, yellow, and blue.
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