Heat Issues

[jmlea0]

I have a obs 99 4 door chevy tahoe.

Problem: My heat only blows cold and heat control doesn't work, and the control for the location of where the air blows doesn't change and its stuck on defrost....

I thought maybe it was the blend door motor so I swapped out the one by gas peddle and it did not fix it. The other two are almost impossible to get to without removing dash. This issue occurred after I added subs and amp to my already installed aftermarket head unit.

Do you think because it is more then one thing maybe it is the climate controls that are bad? Has anybody every had all this happen at once?

Thanks

 

[OR VietVet]

You said this happened after you did the stereo work so I would start there. Got to go back in and check all of what you did because lets say you had the work done at a stereo shop and this happened. You would automatically assume it is something they did/touched while in there. Maybe just remove the heater control and inspect all at the back. Check all fuses and relays. Did you tap in to any power or ground wires while doing your work?

 

[SunlitComet]

White wire for signal on the mode door and light blue for the temperature control door.

Use a meter and any appropriate leads and attach the pos lead to each of those separately at a time and the neg to a solid ground like the dash support beam. As you turn each dial you should see a variably voltage shift that is consistent and smooth on that circuit. If so it is very likely that something went wrong with the motors. The control module itself is also an exposed unit. It is very easy to have something touch a component on it and short something. If the blower works at any of the lower speed settings at the same time that the doors will not move it further narrows the problems to the control module. On the back of the control unit is an inline connector. If no door movement and the fan works on a low speed and there is system voltage on the brown wire but no voltage on the dark green wire next to the black ground wire then it is likely something during the stereo install has accidentally done some damage. If no voltage on that brown wire and no blower output then trace it back to fuse #12 HTR A/C fuse or further back if needed. If you see voltage on the dark green wire at any time other then when blower is switch off the the blower switch is faulty and telling the module to cease function for the most part from user input. Hope this helps. Btw don't forget to check your mode door linkages.

 

[2door2wheel]

i would bet 1000 bucks its the heater controls in the dash. i have done the same thing . twice! they are very fragile.

 

[jmlea0]

Well guys sure enough it was my heater controls in dash! I must have shorted them out some how. I bought a new one and now my heat is back to normal. Thanks for the help

 

[2door2wheel]

Well guys sure enough it was my heater controls in dash! I must have shorted them out some how. I bought a new one and now my heat is back to normal. Thanks for the help

too bad no one took me up on my 1000 dollar bet