I thought it was back to normal. It was for a couple days. Now it's doing a similar thing. When you turn the heat on, it's warm, then gets cool, then cold all within a 30 second period. Then if you turn it off, wait a few minutes, then back on, does the same thing. Wierd that it was working for a couple days then back to having issues. What was that sensor that i supposedly reset when I unhooked the battery then reconnected called. I could have swore that I heard someone calling it an hvac controller. I wasn't sure if maybe that is beyond reseting and needing replacing. What do you guys think? Thanks again for your help. Tim

 

Glad that the re-park procedure had some affect, it aids in the diagnosis, sounds like you have a bad blend door actuator (not sure about the exact location of your faulty one though, there are a few of them). Doing the re-park probably allowed the actuator to get in the posistion for heat temporarily until it faulted again. I haven't heard of guys having any sensor issues that you're referring to though?

 

I have no idea what a blend door actuator is. Sounds like it would be hard to get to. Any other possible problems? It is obviously electrical, just wasn't sure if it could be any other sensor.

 

Those actuator failures are very common, and most likely your problem. From looking at the service manual for my 99, the temp door motor is on the bottom of the HVAC box, in the center. The mode door motor is on the left side, and the recirc door motor is in the top center of the HVAC unit. So basically you want the one on the bottom center. Unfortunately my printer/scanner is inoperative so I can't scan a pic for you It doesn't appear to be an impossible task to replace that motor/actuator though. Not sure exactly how your Tahoe is set up though...

It's a small electric motor that has an arm on it that moves a door in the HVAC unit. One is used for changing modes (foot, face, defrost, etc), one moves a door to switch from fresh outside air to recirculating cabin air, and the one that's giving you a problem moves a door to switch from hot to cold. The dual climate trucks have even more motors than that I believe

 

If you send a PM to Torque Wrench, he can probably give you the exact location of your temp control door motor, along with a part number. He's a great guy and always willing to go above and beyond to help

 

That was very helpful. I had no idea were that thing was. I tried PM'ing torque wrench, but can't find him on the member list. I could probably look around for the part number. Thanks alot for the info. I'll probably get digging for that today sometime.

I'm betting it's a dealership only item, right?

 

Glad to help man, and yea, it's a dealer item. I'll check for the PN, but since there are a few of those motors in the dash, I probably won't find it (I wouldn't doubt if each one of those little motors are slightly different from each other and carry different PN's). I'll be able to find Torque Wrench in the member's list and link you to him though...he might have a _ in his user name (Torque_Wrench).

*EDIT* Here ya go: https://www.performancetrucks.net/fo...er.php?u=45675

 

Hey I'm back! What is the make and model of the vehicle and do you need the part # of the Temp. Door Actuator?

 

not real sure what the vin is right now, but I assume it is the temp. door actuator and it's an 01 tahoe. I probably could get the vin # tomorrow if this doesn't help. Thanks alot for the help. Tim

 

There are 2 Temp. Actuators in that particular application. There is a top and a bottom actuator on the heater box. The part # for the top is 52474810 and the bottom is 89018365.