where did this information come from?

 

http://www.justanswer.com/questions/...-rear-heat-air

I think pulling the fuse may have finally done it after the new control module was in. I'm guessing my old actuator was fine, but I tore it apart and after all of its grinding itself to a stop, I might as well keep the new one in. I'm going to put it through its paces this week, but I'm optimistic that it's finally fixed. It seems to be moving back and forth from hot to cold as needed. Sweet!

 

I have been fighting with my rear heater/ac for about 6 months now. Have been reading everything I could about the problem. I purchased a new Actuator and Control module, but still could not get it to work. The air delivery, head and feet, worked fine, just could not get the temp. to work. WELL, today I found the problem. Seems that the plug that goes in the Actuator had a loose connection. I was able to remove the clips from the plug housing with a tool that is made for this purpose. You can get these at a electronic supply store, maybe Radio Shack has them. Any way, I removed the receiver clips (what the pins in the Actuator goes into), slightly compressed them with a small pair of needle nose pliers, put them back in the holder , reinserter the plug into the actuator, and presto it works fine. Seems that this is a common problem that no one talks about. Just felt this may help others who are having the same problem

 

In my post I forgot to mention that my vehicle is an '03 Tahoe. Of course I think my find could apply to other years also.

 

Control module 15832319 corrects the over travel of the actuator. When the actuator over travels it sets an error in the system. At that point the actuator will stay in a default mode. You have to clear this Error before the actuator will work properly. I tried all the options listed before to clear the error with no results. The one that did work for me was removing HVAC/ECA fuse under the hood. It should be yellow in color and would be 60 watt <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com<st1:address w:st="on">Fuse Square</st1:address></st1:Street> shaped. Once removed Start your car and check the operation of the actuator and rear heat it Should work!!! Turn off the car and reinsert the Fuse.
<OGood Luck <O</O

 

I have the dreaded no heat in rear on my 2003 Tahoe Z71. Does anyone know what voltage should be coming out of the HVAC control module and sent to the air temperature actuator? What color is the wire I need to check voltage on? I do not want to just replace parts. Looks like my actuator has over traveled and I remove the fuse (10 amp HVAC/ECAS fuse in under hood fuse box), but still I can not operate the actuator with the temperature dials, front or rear controls. On the brown wire going into the actuator I get battery voltage all the time, on the white/black I get 2.5-3 volts and on the grey I get 5 volts.

 

Can someone provide a response of value? Has someone had this repair made by the shop? If so what did they say? Can I verify my HVAC Control Module is good or bad?

 

I changed the control module and replaced the actuator. I followed ciscore's directions, but kept getting the same result (actuator moving to hot, then turning to cold after 40 seconds and staying there) I finally disconnected the car battery and waited about 10 minutes. I later found out from a technician that this is the way to clear error codes without a code tool. The dealer told me disconnecting the battery would not make a difference and offered to set up a diagnostic appointment.

After disconnecting and reconnecting the battery and following the above steps, everything seems to be working properly. I struggled with this for about a week before trying the battery fix. Hope this helps save some of you some time.

 

So like a number of people have mention, I too had a Tahoe blowing cold air only. Before researching forums such as this, I took it to the dealer, who wanted $900+ for a new control module and an actuator. I was hoping it would be covered under my 3rd party extended warranty, but no dice there. I said no thank you and started searching. This is the second time it has gone out in 9 years.

Long story short, I ended up getting everything from Amazon.

I started with the control module, AC-Delco 15-73506 Control Module Kit. ($71.50)

You get to the heater by slightly lifting the plastic piece that runs along the back from left to right on the right side. Remove the upper vertical trim piece on the right side, mine has a speaker in it, which has a pinch clip to detach. Be careful. You can start removing the big plastic piece by removing the screw/**** thing at the top and start popping it out back to front. Be careful if you have a power plug. Again, a pinch clip. It is weaved in at the front near the lower outlet, so you just need to fish it out.

Once it's off, you can get to the front actuator (top/bottom damper), the control module in the middle, and the hot/cold damper actuator toward the back. One of the posts in this form or another had a picture.

I unplugged and replaced the control module, but it didn't fix my problem. This may have been because I didn't clear the codes, but I went forward and replaced the actuators also. The actuators were the same and were AC-Delco 15-72972. (about $86 each).

That still didn't seem to fix it, so I did the fuse trick, both on the 60A fuse and the 10A fuse - still no fix.

Finally, I stumbled onto the battery trick. I fully disconnected my battery for about 30 minutes. Then reattached. When I started the truck, I heard the calibration mode start and the top/bottom damper cycle between top and bottom (note that I had the fan fully on, which helped because I could hear it). They say not to adjust it during calibration, so I let it run for a about 2 minutes, and turned it off.

They also say not to try to run the actuators unless they are connected into the heat unit. I didn't test my waters.

I know I'm not really adding anything terribly new, but I'm not super handy and I put together a lot of stuff from a few forums into a single post. Hopefully I can save someone else some time.

All total, I was out for about $300 + $100 diagnostic fee from the dealer. Sure beats the $900+ they started with.

May The Force Be With You

 

Welcome to the forum and thanks for the DIY info. It will probably help a lot of folks in the future.