The driver's seat cools fine. However the passenger seat does not. I brought to dealer last week and they claim that the fan is blowing cool air corrrectly so therefore it meets the standards. I explained that so what if the seat doesn't cool. Service Manager asked me to bring the car back in. Any thoughts?

Using a Tech 2 scan tool and a multi-meter, the dealer can verify the HVC Control unit is commanded to the desired state, the seat blower fan is operating, both upper and lower thermo-electric elements are cooling, and the thermisters are registering colder air (at the output of the TEC.) The tool can't verify air is moving up the back of the seat however. Your post doesn't mention if the problem is isolated to the seat cushion, seat back, or both.

These seats don't necesarilly drop the temperatures appreciably in a "scant two minutes" as the brochures implied. It can take up to ten minutes for them to reach full potential.

Try these easy, no-tools required checks yourself:

1) Enable the offending seat's cooling function (on High) and slide the seat fully forward.

2) Tilt the seatback forward and with the aid of a flashlight, verify the duct leading from the lower cooling module to the upper seatback is connected. It's an accordian-shaped, black plastic piece about 2" wide at the base of the rear seatback. If it's disconnected, the system won't seal properly and it will blow air into the area behind the seat and neither the lower cushion or seatback temperature will change much -if at all. These ducts have a habit of coming loose or tearing. Both were disconnected when I purchased my car. If loose, a tie wrap works great to seal the ducts back together. If torn, use duct tape (no pun intended) until you can get a replacement duct.

3) If the duct is connected, pull it loose and feel for yourself to verify that cool air is coming out. If not, the dealer gets to bask in your presence once again.

Good luck!

CC :seeya

I am completely confused. The owner's manual and the settings on the climate control on my 2008 XLR imply that I can get cold air through my seats. (My wife has an STS and ice cold air streams through her seats.) I dropped my car off at the dealer today for warranty work including fixing the cooling in the seats. They told me the XLR seats only have an internal fan to "cool" the seats. When climate control is set to high or low cooling for the seats, the fan just recirculates the air from inside the car through the seats. Does that sound right? :rolleyes
Thanks,
Steve (Sli1)

Hi Steve!

Your tech needs to read the shop manual. Each seat has a blower fan that blows air over a thermo-electric cooler located in the set cushion and seat back. The polarity of the TEC is reversed to alternate between heating or cooling, as selected from the HVAC control unit.

A certified XLR tech would know this.

CCC :cheers

Hi Steve!

Your tech needs to read the shop manual. Each seat has a blower fan that blows air over a thermo-electric cooler located in the set cushion and seat back. The polarity of the TEC is reversed to alternate between heating or cooling, as selected from the HVAC control unit.

A certified XLR tech would know this.

CCC :cheers
Just curious... why then, does the seat not get cool (or warm, for that matter) until the a/c (or heat) comes on in the cabin?

Just curious... why then, does the seat not get cool (or warm, for that matter) until the a/c (or heat) comes on in the cabin?

I also have noticed this???

Interesting . . . I've never noticed the heating/cooling function of my seats being dependent on the HVAC control unit. I'll check mine out when I get home from this trip. I thought about it on the way to the hotel tonight and it makes sense, since one would normally use the cooling function on a hot day, coupled with air conditioning and vice-versa for heat.

I don't carry the shop manuals on trips, (if you've seen how big and heavy they are, you know why) but I do bring a smaller manual, used to train the techs. It's got a schematic of the seat heating/cooling circuit and I was suprised to see it doesn't look like it needs the cabin AC or Heating enabled on the HVAC control unit to operate the seat's heating/cooling function. For those interested, here's a quick and dirty run-through on how these seats do their thing:

The "brains" of the seat's heating/cooling function are contained in a Climate Controlled Seat module under each respective seat. Three inputs power and control them:

1) Battery voltage --via a 15 amp fuse in the passenger side toe compartment fuse block.

2) Ignition voltage via the Run/Crank relay circuitry in the Body Control Module.

3) A pulse-width modulated control signal from the HVAC control unit to tell the Climate Controlled Seat modules which setting (COOL HI/LO, etc) to work toward.

There are two heated-cooled seat ventilation modules in each seat, one for the cushion and one for the seat back. Voltage is supplied to each to control ceramic elements called thermo-electric coolers, that can be made to change from heating to cooling by reversing the polarity. Air is blown across the TECs by a blower located under the seat. By comparing a reference voltage to the blower and feedback from a thermister, the Climate Control module adjusts the blower speed and voltage to the two TECs to maintain the desired temperature. Compared to a grid-type heating unit, the TECs take considerably longer (10-12 minutes) to heat the seats. While my lower cushions work well, the seat backs put out 25% of the heating or cooling in comparison. The ducts are okay, so maybe I'll experiment with an aux blower using a small 12v computer fan located further downstream.

Thanks for telling me about the operating parameters with the HVAC control unit; I'm curious about mine now. Anybody else care to chime in on this?

CC :seeya

My driver's seat cools even with the windows and top down and I have used this feature several times and was impressed how well it worked not having to turn the A/C on until it got hot outside. It doesn't freeze you out, but if you feel the seat cushon it is definately cool to the touch.

My passenger's seat does not heat or cool. Investigating this, I found the plastic duct from the seat bottom to the seat back was broken and a piece was even missing. Additionally, the blower under the seat was not coming on. Checking the blower connector I found it was getting power, further investigation revealed that the connector on the blower side had two wires reversed, obviously by the company that built the blower. It could have never worked and the two reversed wires blew an internal fuse in the blower assembly. I bought the car second hand so I guess the original owner never tried to operate the seats.