2004 Suburban A/C problems

**wardo5757** · 08-17-2009, 03:29 PM

Hello all!
I have done considerable searches on this subject and haven't found anything specific to my problem so go easy on me please.... I have an 04 suburban LT with dual climate control and the A/C will blow hot for no apparent reason. Once I have turned the ignition off then restart the engine it will blow cold again. I have discovered that if I keep the temp set very low it will not get stuck in the heat mode. After all the searching I am fairly confident the problem is one of the blend doors.

I took my dashboard apart this past Saturday just to explore and realized that I don't have a clue what I'm even looking for..... I don't know which motor is bad, or if it's bad? Is it just a sticking door? It seems a LOT of hours will go into fixing this, so should I replace all the motors and doors once I get the evaporator unit out? do I need to take the entire unit out?

I have a Haynes manual for my vehicle, but it's pretty much useless for the more technical issues, is there another manual you guys would recommend for this task?

Thanks in advance for the help
Eddie

**unplugged** · 08-17-2009, 09:31 PM

Sounds more like a high or low pressure problem. There are both high and low pressure switches that are designed to protect the compressor/system. The blend door controls the air flow and wouldn't have that much effect on the temp.

Your mechanic should be able to diagnose your problem and provide you with an estimate for the repair. With that info you can decide what your budget can handle. You could try to add some freon just to see if it is a low pressure issue. If you have a system leak, any freon you add will only help temporarily.

**wardo5757** · 08-17-2009, 11:09 PM

Originally Posted by unplugged

Sounds more like a high or low pressure problem. There are both high and low pressure switches that are designed to protect the compressor/system. The blend door controls the air flow and wouldn't have that much effect on the temp.

Your mechanic should be able to diagnose your problem and provide you with an estimate for the repair. With that info you can decide what your budget can handle. You could try to add some freon just to see if it is a low pressure issue. If you have a system leak, any freon you add will only help temporarily.

Thanks for replying unplugged, I forgot to mention that the passenger side and rear a/c is still frosty. The unit is charged fine, it just blows hot air intermittently from driver side.

**unplugged** · 08-18-2009, 09:55 PM

Originally Posted by wardo5757

Thanks for replying unplugged, I forgot to mention that the passenger side and rear a/c is still frosty. The unit is charged fine, it just blows hot air intermittently from driver side.

Ahhh.....the rest of the story. Sounds like you are on the right track. Check the post for "exploded views" If you dig in there you might find what your looking for.

**wardo5757** · 08-22-2009, 07:27 PM

do you think i wil need to pull the dashboard to get to the problem? is there a manual you would recommend to do this work?

**moosetags** · 08-22-2009, 08:52 PM

Originally Posted by wardo5757

Hello all!
I have done considerable searches on this subject and haven't found anything specific to my problem so go easy on me please.... I have an 04 suburban LT with dual climate control and the A/C will blow hot for no apparent reason. Once I have turned the ignition off then restart the engine it will blow cold again. I have discovered that if I keep the temp set very low it will not get stuck in the heat mode. After all the searching I am fairly confident the problem is one of the blend doors.

I took my dashboard apart this past Saturday just to explore and realized that I don't have a clue what I'm even looking for..... I don't know which motor is bad, or if it's bad? Is it just a sticking door? It seems a LOT of hours will go into fixing this, so should I replace all the motors and doors once I get the evaporator unit out? do I need to take the entire unit out?

I have a Haynes manual for my vehicle, but it's pretty much useless for the more technical issues, is there another manual you guys would recommend for this task?

Thanks in advance for the help
Eddie

I recently experienced the exact same problem on my '04 Sub 2500. I finally took it to the GMC dealer. It was a bad ac door actuator motor in the dash on the driver side. It ended up costing over $500 to fix it. A month late, the passenger side failed. I ended up replacing the right and center actuator motors at another $900. If you already have your dash apart, you can probably buy the motors and replace them yourself and same a bunch. Based on my experience, I would suggest replacing all three actuator motors while you have the dash apart. I was told that these motors are sealed units and are not repairable.

Please let us know how it comes out.

**bill190** · 08-22-2009, 09:27 PM

Try a "reboot"!

Remove a battery terminal for 10 minutes, then reconnect.
Turn ignition switch to on, but don't start.
Wait 1 minute.
DO NOT touch any buttons in the vehicle during this minute.
Then start vehicle and let idle for 5 minutes.
Drive above 45 mph as soon as possible.

This "reboots" all the computers in the vehicle including the A/C which then "resynchronizes" the actuator doors during the power-up.

This also reboots the engine computer and the idle and driving above 45 mph helps it to "regain" its operating memory.

If this does not work, you would need a GM Factory Service Manual set which would have complete troubleshooting instructions for this problem as well as complete part replacement procedures. Order from helminc.com or a GM dealer.

You would also need to know how to use a multimeter along with the instructions in the manual. How to use a multimeter...
http://www.google.com/search?hl=en&s...imeter&aqi=g10

**wardo5757** · 08-22-2009, 11:37 PM

[QUOTE=bill190;168992]Try a "reboot"!

Remove a battery terminal for 10 minutes, then reconnect.
Turn ignition switch to on, but don't start.
Wait 1 minute.
DO NOT touch any buttons in the vehicle during this minute.
Then start vehicle and let idle for 5 minutes.
Drive above 45 mph as soon as possible.

This "reboots" all the computers in the vehicle including the A/C which then "resynchronizes" the actuator doors during the power-up.

This also reboots the engine computer and the idle and driving above 45 mph helps it to "regain" its operating memory.

If this does not work, you would need a GM Factory Service Manual set which would have complete troubleshooting instructions for this problem as well as complete part replacement procedures. Order from helminc.com or a GM dealer.

You would also need to know how to use a multimeter along with the instructions in the manual. How to use a multimeter...
http://www.google.com/search?hl=en&s...imeter&aqi=g10[/QUOTE

I tried the reboot, it was a nogo unfortunately. I will call the dealership on Monday and ask for the manuals on my Burb, I'm thinking I will pull the entire evaporator unit and rebuild it. It's too much damn work to keep going in there i think...

Just a couple of questions, I've read that the blend door gaskets got old and sticky, should I change those as well? Do I need to pull the entire unit to change these door actuators and door gaskets?

**bill190** · 08-23-2009, 12:02 AM

I don't know about your specific year, but I've not heard of anyone going to any extreme trouble to replace an actuator. So far as I know, they are fairly accessible.

As to replacing other parts, I would say use your judgment. On some projects I replace everything. On other projects everything is in good shape and I only replace the faulty part.

**wardo5757** · 08-23-2009, 10:57 AM

Originally Posted by bill190

I don't know about your specific year, but I've not heard of anyone going to any extreme trouble to replace an actuator. So far as I know, they are fairly accessible.

As to replacing other parts, I would say use your judgment. On some projects I replace everything. On other projects everything is in good shape and I only replace the faulty part.

Bill, do you, or anyone else know how to pull off the grab bar? I have reahed up inside and removed the two white retainer clips but the sucker will not budge?

Any ideas?