Poor rear heating - EXT & XL Models

[04TBEXT]

I know for most it's warm out, but sooner or later were gonna run out of warm weather & face the cold. I know that the rear heat in my '04 EXT flat out sucks when it comes to producing hot air in the winter time. During higher RPM's there is some heat...at idle it's a flat out joke. Even sitting in the driver's seat, with air directed from the roof vents, I feel like I'm taking a "cold air shower" when sitting at the stop light....BUT NEVER FEAR...UNDERGM IS HERE!!!
GM now has a service bulletin out which utilizes a rear heat coolant pump to increase coolant circulation to the rear heater core. Haven't put one in nor haven't seen one done, but it's nice to know that my back seat passengers may be able to unzip their jackets and remove therir gloves when riding in the back seat. If anyone's interested..let me know and I'll post you some info...

[GroundChuck]

Does this apply to '05s also? My EXT has not seen a winter yet.

[04TBEXT]

Bulletin # is 05-01-37-002, and yes, it does apply to '05 EXT & XL models.

[dheida]

I have the exact same problem in my 04 EXT. It's just the overhead though, the floor vents in the rear blast out cold or hot whatever I have it set on, but the overhead vents blow what seems like outside air. I took it into the dealer and they said Chevy is researching it and the dealer did nothing. Email me @ thousand_julys@hotmail.com if you have any info.

[04TBEXT]

dheida..I don't have e-mail access...PM me with a fax number and I'll send it to ya. GM is done with research...their is now an auxilliary pump kit available. I have already installed it on my vehicle...it's 70 - 80 degrees, so testing its efficiency is useless @ this time...04TBEXT

[dheida]

I looked up that bulletin number and found the page that talks about it. Do they charge for that component and its installation or (I would think) is it covered under warranty?

[dheida]

I got the pump installed. It seems to have done the trick for the cool air from the rear vents. I could only try testing the heat for about 5 minutes before it got too hot to have it on anymore, but it did seem at least marginally better.

[dheida]

Now that it's winter, and although it's 50 flippin degrees out when it should be about 10, I've had a chance to test this "new pump". The overhead vents still don't blow warm enough to have on even after letting the vehicle "warm up" for about two hours. Anybody have any additional information on this?

[ieatglue]

Our EXT only has cold air in the back. When you set it on the highest temp, it doesn't seem to help, still cold air (the bottom vents have hot air tho). But in the summer, all is well and we get ice cold air :thumbsup:

[Dacomputernerd]

So is this for the 05 EXT aswell? Right now it takes a long time for the rear roof vents to even get warm.

[EnvoyXL]

From what I was told by the service tech was that we dont have rear heat, just rear A/C. When you turn the rear blower on the A/C turns on and you can turn it to full hot and it just makes the A/C warmer by adding outside air from the engine compartment. The only way I think this could be fixed is by adding a switch to the A/C compressor so you could turn it off and just run hot air when you actually want heat.

[dheida]

That doesn't make much sense....the floor vents in the back blow what they should, but I guess I don't know exactly how the vents are routed or what drives them. Also, you would think the non-EXT models would have the same problem with the overheads in their back seats.

[firelady1530]

Just had my 05 TB in for the same issue. Less than a month ago. The dealer said that there was no problem, but it is nice to know that someone else is having this issue. Mine is an EXT LT, and while I love it, that particular issue is driving me nuts. I have an appointment on Monday at the dealer for something unrelated to this, but will definitely bring it up. Good to know I am not alone!:p