Chevy Silverado
305 cid
tech = JK
question = Hello JK. Please help me, I'm at my wit's end. My '95
Chevy truck is having AC/vent problems.
The fan speed and fan work correctly. The heater control and heating
work correctly.
The fresh air/recirc button never illuminates or has any affect. The
AC button never illuminates or turns on the
AC compressor. The vent selector has no affect. Air only comes out of
the floor vent, regardless or the setting.
I just replaced the dash control unit with a new one, and it didn't
change the symptoms at all. I checked and even checked continuity on the
related fuses.
I jumped the AC high pressure sensor and it didn't change a thing. I
hotwired the AC compressor on, and nice cold air blew out of the vent
immediately, so I assume the AC system is working correctly. I've gotten
in the dash and reseated all the plugs I could reach. When I swap
between the new and old control units nothing changes at all.
Once in a while one of the servos will move, but rarely. The air might come out of the upper
dash vents when I first start the truck but
switches to floor vent within a couple seconds. Sounds like one of the
other flaps might move once in a while, but rarely.
Can you please tell me if these symptoms ring a bell with you, of at
least offer a suggestion on how to troubleshoot this thing?
JK:
Sounds like you have several different problems here. For the vents switching, sounds like a
vacuum problem. There is a vacuum reservoir tank that hold vacuum to move the vents
actuators. If vents switch when hitting gas, or when idling, then need to find source of vacuum
leak. Either the tank or the hose that feeds the switch.
The compressor not coming on is electrical. There is also a low pressure switch, a compressor
relay for the system. Make sure to check ALL fuses also.
Back
305 cid
tech = JK
question = Hello JK. Please help me, I'm at my wit's end. My '95
Chevy truck is having AC/vent problems.
The fan speed and fan work correctly. The heater control and heating
work correctly.
The fresh air/recirc button never illuminates or has any affect. The
AC button never illuminates or turns on the
AC compressor. The vent selector has no affect. Air only comes out of
the floor vent, regardless or the setting.
I just replaced the dash control unit with a new one, and it didn't
change the symptoms at all. I checked and even checked continuity on the
related fuses.
I jumped the AC high pressure sensor and it didn't change a thing. I
hotwired the AC compressor on, and nice cold air blew out of the vent
immediately, so I assume the AC system is working correctly. I've gotten
in the dash and reseated all the plugs I could reach. When I swap
between the new and old control units nothing changes at all.
Once in a while one of the servos will move, but rarely. The air might come out of the upper
dash vents when I first start the truck but
switches to floor vent within a couple seconds. Sounds like one of the
other flaps might move once in a while, but rarely.
Can you please tell me if these symptoms ring a bell with you, of at
least offer a suggestion on how to troubleshoot this thing?
JK:
Sounds like you have several different problems here. For the vents switching, sounds like a
vacuum problem. There is a vacuum reservoir tank that hold vacuum to move the vents
actuators. If vents switch when hitting gas, or when idling, then need to find source of vacuum
leak. Either the tank or the hose that feeds the switch.
The compressor not coming on is electrical. There is also a low pressure switch, a compressor
relay for the system. Make sure to check ALL fuses also.
Back
Chevy Silverado A/C Problems
1999 Chev. Silverado 6.0 Vortec
Work done to repair this problem = mechanic replaced the motor in middle of heater/ac but did not
fix the problem.
GM tech = one who knows heater/ac
question = The heater/ac makes a thumping noise in the dash on the passenger side. It seems to
be in the fresh air/inside air motor or solenoid that changes the door. It acts like it is trying to open
or close the door but is hindered. It thumps, thumps, thumps then stops, after a few minutes it
does it again. If the button is pushed for inside air it seems like a grinding noise. It also does it
when changed from heat to AC. Where is the motor or solenoid which changes that door?
Work done to repair this problem = mechanic replaced the motor in middle of heater/ac but did not
fix the problem.
GM tech = one who knows heater/ac
question = The heater/ac makes a thumping noise in the dash on the passenger side. It seems to
be in the fresh air/inside air motor or solenoid that changes the door. It acts like it is trying to open
or close the door but is hindered. It thumps, thumps, thumps then stops, after a few minutes it
does it again. If the button is pushed for inside air it seems like a grinding noise. It also does it
when changed from heat to AC. Where is the motor or solenoid which changes that door?
GM Tech JK:
To replace the recirculate actuator, you need to remove the top of the dash. You may not need to
replace the actuator though. This door actuator does not have anything to do with the temp. So a
noise in that door can.t be this motor.
Try a reset...
First, disconnect the battery for a few minutes. Then reconnect, start truck, and let it run for 3
minutes without touching any of the A/C controls. This is a sort or reset for the electric door
actuator motors.
To see that door and motor, remove the glove box, release the tabs on the inside of the glove box,
you do not have to take it off, just open all the way past the stops that keep it from swinging al the
way down. When you do this, you should be able to see the recirculation door, it has foam on it
with a plastic grill. Turn on the a/c, push on the door and turn the system to recirculation and ses if
it moves, and if this is the one giving you the noise.
To replace the recirculate actuator, you need to remove the top of the dash. You may not need to
replace the actuator though. This door actuator does not have anything to do with the temp. So a
noise in that door can.t be this motor.
Try a reset...
First, disconnect the battery for a few minutes. Then reconnect, start truck, and let it run for 3
minutes without touching any of the A/C controls. This is a sort or reset for the electric door
actuator motors.
To see that door and motor, remove the glove box, release the tabs on the inside of the glove box,
you do not have to take it off, just open all the way past the stops that keep it from swinging al the
way down. When you do this, you should be able to see the recirculation door, it has foam on it
with a plastic grill. Turn on the a/c, push on the door and turn the system to recirculation and ses if
it moves, and if this is the one giving you the noise.