Seat heater element testing
First brief description of operation
The heated seats are powered by the driver seat memory module (under seat) the voltage to the heater elements is varied to maintain the desire temperature. The bottom element has a thermistor built in to provide temperature input. Based on input from sensor and input from heater switch (low,high,off) the seat module supplies the current to the heating elements. There are TWO elements one in the bottom and a separate one in the back. The seat elements are in wired in series -- thus if one burns out they both quit working. Both seats share the same fuses and circuit breakers -- if one side works - these are not at fault
The easiest way to test switch and sensor is using a scan tool -- if they pass then test elements using an ohmmeter.
I am afraid you will need to have access to an good Ohmmeter to conduct some tests. Search you tube for operation instructions that might be similar to the meter you have if you need help.
Totally inoperative seat heater one one side - possible causes in no particular order: heater switch, bottom heater element, seat temperature sensor (part of bottom element), back heater element, seat module and wiring under seat.
You can test some of the components with ohmmeter (no scan tool)
Picture 1 -- show the locations and resistance specs for the tests -- note you will disconnect the connectors and then the place the ohmmeter leads on the male terminals of the connectors or the heater switch. It does not matter which one is red or black - just be sure to test the proper ones - confirm this not only by my pictures but the color of the wires also.
Picture 2 - shows all the wiring from the bottom view of seat - the four wire heater connector should be #1 - confirm with wire colors
Picture 3 - the four wire connector test temperature sensor = measure resistance between terminals D and C should be approx 3-11 K Ohms if way to high or low temperature sensor is bad and the bottom seat element needs replaced. If ok measure resistance between terminal A and B should be 2-4 Ohms (this is the resistance of BOTH elements wired in series with 1-2 ohms each) If not ok the problem is one of the two seat elements - you must test the back element resistance. If ok problem is not the heating elements
Picture 4 - the two wire connector -- could not find location -- should be near the back of the seat - not sure if accessible from bottom or if seat back (the large plastic part) has to be removed. The resistance of the element should be 1-2 ohms. If not ok seat back heating element is bad. If seat back tested ok but the previous test was not - seat bottom heating element is bad
Picture 5 seat heater switch -- it shows a 8 cavity connector at the switch but only uses two wires? unplug the switch and measure resistance of the switch (not the wires) between these two locations. Ohmmeter should read "out of limits" ( the same it reads when measure resistance with the leads not connected to anything!) in off, close to 4530 on low and close to 4530 on high
Hope this helps and one of these proves to be faulty.
Let me know if you have questions, I will try to help
