First off I'm new to the site, I was on the other site but used it for nothing more than research. Today I changed the serpentine belt, thermostat, temp sensor, and coolant on my '03 EXT. When finished, I started it up and the rear A/C starts clicking. It goes away after a min or two and starts blowing air. Later I start it up again and it does the same thing; clicks then goes away. I did a search to see if this has been a topic before but found nothing that matched my symptoms. There was a thread where someone had posted that it needs to "calibrate" after the battery being disconnected and resetting the computer. Would this be what is going on here as well? Any insight provided would be greatly appreciated. Thank you in advance.
Rear A/C clicking
- Thread starter benz01
- Start date
Voymom
Member
- Feb 3, 2012
- 2,523
benz01 said:
Sounds like your rear actuator is going bad. It's a common issue when disconnecting the battery. I have had the same issues, there are 2 fuses for the rear actuator, a 10 amp and a 30 amp. Try turning your vehicle off completely, remove one fuse at a time for 30 seconds. Put it back in and turn the truck on, I would recommend waiting a day or 2 before pulling the other fuse to see if the clicking stops. I had this same issue, and upon pulling the 10 amp fuse the clicking has now stopped and I can use my rear HVAC anytime, at any speed and setting without the noise.
A fellow member here sent me this picture showing the fuses, so maybe this will help.
The secret to a successful fuse-pull recalibration is to put the fuse in, then turn the ignition on (not necessary to start the engine) and NOT TOUCH any HVAC controls for the next 90 seconds. The HVAC system will run each of the actuators from end to end, trying to discover the endpoints where the actuators stop moving. If you interrupt this process by pressing any buttons, the recalibration is faulty and the clicking might not stop.
The clicking may also not stop if the actuator failed. Often, due to poor design, the gear train inside the actuator is broken or skips a tooth, when the recalibration happens. The recalibration is a very stressful time in the actuator's existence, due to a software design problem.
So the fuse-pull is a potential fix, not a guaranteed one.
The clicking may also not stop if the actuator failed. Often, due to poor design, the gear train inside the actuator is broken or skips a tooth, when the recalibration happens. The recalibration is a very stressful time in the actuator's existence, due to a software design problem.
So the fuse-pull is a potential fix, not a guaranteed one.
the roadie said:
Thanks for the tip. This morning I got in started it up, NO CLICKING. The blower works and it pushes cold air, I didn't test the heat due to the humid morning here in KC. I'm just wondering if this is just a calibration issue that will show up after resetting the computer or a sign of something going out. Thanks again for sharing your knowledge.
Uncle Blazer
Member
- Dec 8, 2011
- 263
the roadie said:
should the system be at a certain setting prior to the pull/recalibration? Is this process effective(relatively speaking) without disconnecting the battery first?
benz01 said:
It's a design issue and it has the potential to return anytime you disconnect the battery from the truck, or if you disconnect the HVAC module from it's wiring harness. The recalibration routine has the potential to stress the actuators enough to break something (usually a gear inside the actuator).
If you find the actuator is still clicking and you feel up to trying this, you can save yourself some money.
http://gmtnation.com/f23/successful-re-index-mode-actuator-cheap-actuator-fix-3492/