Now that its not 110 degrees here in Phoenix I am finding out that the rear heat isn't working in my 2002 SLT. Fan blows fine on all speeds when set with either front or rear control *****, but its really cold even when the front starts to blow hot. I read the thread on the blower resister, but I'm not sure that's what the problem is as all speeds are working.

In 2008 I brought the truck into the dealer as the defrost light was blinking. According to my records, they replaced the rear A/C controller part #55056249-AE and said the "blend and mod doors weren't working."

A search in the manual mentions the blend air door and actuator. It says that the heater-A/C control module will store a DTC. Should I start here?

 

Magoo - you mentioned the speed settings but I have to ask the obvious. Is the temp control set to HOT on the rear controls?

 

Sounds to me you still hve a rear blend door problem. You have to take off the rear seats to get to the wheel well from the inside. The whole thing is located in the inside passenger rear wheel well. I know some members have done that and you can do a search to find them. HTH.

 

assuming you have the heat controls in the rear set to heat then dan nailed it, the blend doors and rear heater core are behind that plastic panel on the passenger side of the third row foot-well

 

Is the 99's rear heat different??
The vents above on the roof are blowing cold air(on mine), but the ones on back of center consel blow hot.

Whats wrong with mine?

 

On a 1999 I believe that the overhead system for the rear only has A/C and just a regular blower. There should be not heat on that year. I think only 2000-2003 has a rear heat included. If by chance you do have heat there, you will see a **** indicating hot air like the front.

 

started to think about it, and i dont have a temp control **** there. But thank you for info. I thought maybe temp was controlled up front or somthin.

 

Thanks for the info to date. Both front and rear ***** are set to hot.

I'll have to start removing the 3rd row when I get some time. Is the Blend Doors and Heater Core expensive? Can anyone describe what they look like and how can I tell if one or both are bad. Finally, should I have friend w/shop search for error code?

The part/labor that was replaced by dealer was $500. Not sure if this is the same part as the problem last time as that was a blinking defrost light. If you guys are saying it still sounds like the same problem are you saying its the same part as well? I've learned a lot about the truck since than and would probaly try to do the fix myself.

 

the rear vents would be separate from the blinking defrost light, the defrost light will blink when there is a problem with either the heated mirrors, or heated rear window (these are the two things controlled by that defrost button, front defrosters are an option on the directional **** in the dash)

it should be pretty easy to tell if one of the blend doors is broken, they are only plastic, you can check the heater core by feeling the coolant lines running under the truck, when the engine is hot they should both be warm-hot, if one is COLD and one is hot then you have a clogged heater core, if both are cold you still probably have a cold heater core, unless it was bypassed under the hood by a previous owner.

 

Are the blend doors what i hear when i change from defrost to mix, are they suppossed to be kinda loud when changes, mine kinda goes CLUNK.