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Seat heat not working (driver's side) - Can anyone help me troubleshoot?

23K views 8 replies 5 participants last post by  WesH8398 
#1 ·
The passenger side works great, but my driver's side heated seat doesn't seem to be working. I don't know that it ever has, honestly. My wife was just commenting on how nice and warm her seat was getting the other night, and so I turned mine on and really didn't notice anything. Then she was driving the car yesterday and informed me that the driver's side definitely wasn't working.

When I press the button on the climate control, I can hear the faint "click" somewhere in the door or dash area, but nothing seems to heat up. Are there any places in particular that I should be looking? Which is the heater connection under the seat? Do those go bad? Could it just be a fuse, maybe?

Any suggestions would be greatly appreciated! Thanks!
 
#2 ·
The seat gets hot, you'd know if it was on. Just sit in the passenger seat and turn it on..

Behind the seat at the bottom there's a flap, lift it up. A black wire coming out from between the upper and lower sections connects under the seat. That's the power wire to the back of the seat. The bottom cushion connects to the upper cushion under the seat as well (i think). I'll look for some pics.

Other than that, fuse? It's easy to overlook the reconnection. I forgot on removal #3 last summer and I didn't notice until the first day it was 30 degrees and I hit that button.
 
#9 ·
Unfortunately I've had no luck solving the problem either. Still not working. Ugh.
Any luck on those pictures? I've taken a look under the seat to try and make sense out of the mess under there, but haven't had much luck identifying what's what.

I'm thinking maybe I should/could test voltage presence at the rear fuse box (and/or other fuse boxes), but I'm not overly comfortable using my volt/ammeter. It's got a billion settings on it's dial with lots of symbols that I'm not at all familliar with. Regardless, I think I should test that power is indeed being sent to the seat, and that'll help me narrow down the problem area (hopefully). Could anyone provide tips on how I might do this?

Thanks again!
 
#3 ·
HEATED SEATS DESCRIPTION AND OPERATION

The driver and front passenger heated seats each consist of the following components.


•Heated Seat Switch
•Heated Seat Module
•Seat Cushion Heater Element
•Seat Back Heater Element
•Temperature Sensor
•Climate Control Panel (CCP)
•Rear Integration Module (RIM)
•LF FRT HTD SEAT MOD 10 A
•RF FRT HTD SEAT MOD 10 A
Power and Ground
Battery positive voltage is supplied to both front heated seat modules from the rear fuse block IGN 3 Fuse. This voltage is used to power up the heated seat modules allowing the heated seats to operate only when the ignition switch is in the ON position. Battery positive voltage is also supplied at all times to the left front heated seat module from the LF FRT HTD SEAT MOD fuse located in the left rear fuse block and to the right front heated seat module from the RF FRT HTD SEAT MOD fuse located in the right rear fuse block. This voltage is used by the modules to supply power to the seat heating elements. Both modules are grounded through the module ground circuits and G307.

Heated Seat Operation
The driver and passenger heated seats are controlled by separate heated seat switches. Both switches are located in the CCP. When a heated seat switch is pressed, the CCP sends a class 2 message via the serial data line to the rear RIM indicating the heated seat command. In response to this signal, the RIM momentarily sends a 35 millisecond one shot pulse signal that is pulled low through the heated seat high/low signal circuit to the heated seat module. The heated seat module then applies or removes battery positive voltage through the element supply voltage circuit of the seat heating elements. The RIM then sends a class 2 message back to the CCP to either illuminate or turn off the appropriate temperature indicator.

Temperature Regulation
When the ignition is turned to the ON position, the heated seats will initialize in the OFF state. With each activation of the heated seat switch, the heated seat module will cycle the temperature setting in the following manner: HIGH, LOW, and OFF.

The heated seat system is designed in order to warm the seat cushion and seat back to approximately 42°C (107.6°F) when in the high heat position, and 37°C (98.6°F) when in the low heat position. The heated seat module monitors the seat temperature through the temperature sensor signal circuit and the temperature sensor (thermistor) that is located in the seat cushion. The temperature sensor is a variable resistor, it's resistance changes as the temperature of the seat changes. When the temperature sensor resistance indicates to the heated seat module that the seat has reached the desired temperature, the module opens the ground path of the seat heating elements through the heated seat element control circuit. The module will then cycle the element control circuit open and closed in order to maintain the desired temperature.

Load Management
The ON/OFF status of the heated seats is reported to the RIM through the status output signal circuit of each heated seat module. During Heated Seats Load Shed Level 1, and the RIM recognizes that the heated seat status signal is active, it will cycle the heated seat operation 16.0 seconds ON and 4.0 seconds OFF. During Heated Seats Load Shed Level 2, the RIM will signal the heated seat module to cancel the heated seat operation and send a class 2 message to the CCP to turn off the appropriate heated seat temperature indicators.
 
#7 ·
Well, I checked all fuses and everything seems fine. I looked under the seat to try to pick out anything that looked wrong, but I barely knew what I was looking at, so that didn't help at all. Unfortunately I'm not too sure where to go from here. It doesnt appear that I'm going to be able to fiddle with the under seat stuff much without taking the seat right out...
 
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