Front passenger heated seats not working

Hi,

There are a few fuses to check. I attached two pics below. The first shows the fuses. The second pic shows the wiring to the passenger seat.

Based on your description, I suspect either there is a faulty ground for the seat or the switch itself is bad and can not control the load placed on it.

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I had to provide pics in two parts simply because they are from different pages. However, you can see where the wiring connects from one to the other.

First, check the fuses I highlighted in the first pic. In addition to simply checking the fuse, I need you to confirm there is power both to it and out from it. Here is a link that you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

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Next, confirm the ground is in good condition. If you look at pic 3, you will see the ground I am referring to. It is under the seat. (G651) Make sure the wire to the ground isn't damaged.

Next, pics 4 and 5 show fuse location. Pic is under the dash, passenger side and pic 5 is the fuse box under the driver's side. I highlighted the fuses to check.

Let me know what you find.

Joe

The first thing to check would be the fuses, there are 3 that power the heated seat controller and the seat heating elements. Fuse number 5 and fuse 20 in the passenger side fuse box under the dash and fuse number 26 in the drivers side under dash fuse panel.
Because it is both heaters at the same time I would suspect it is in the control or power feeds and not the elements themselves. The other item to check is the seat heater relay in the same fuse panel as fuses 5 and 20. It turns on when the key is turned on, if you can hear or feel it click when the key is turned on it has the control signal, but it's still possible that the contacts have failed in it. To test that the easiest way is to swap the relay with another one that is working and see if now the seats work and the other system doesn't. The one next to it controls the right rear window and should be the same part number. If you try the window and verify it works, then swap the relay, if the window still works the relay is okay, if it doesn't work the relay is bad, then you just buy a new relay. To test the fuses faster you can use a simple test light. It's easier and shows if there is actually power on both sides, I've seen more than a few fuses that looked good that were not.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester
https://www.2carpros.com/articles/how-to-check-a-car-fuse

It's also possible the seat heater control module has an internal failure. A scan tool like a dealer has would show if there was a fault in that. However I would check the fuses and relay first. Then return and tell us what you found and we can proceed from there.

Okay, if the fuses and relays are okay then it is time to test for powers and grounds at the seat control module. The module is under the passenger seat and you will need to remove the seat to get to the wiring connectors for testing. This testing can result in the need to use a dealer level scan tool to reinitialize the passenger side occupant detection sensor as it will be disconnected from the vehicle during the testing.

To remove the seat you will need to remove the trim covers on the legs of the seat to get to the 4 bolts underneath them. Pull the seatbelt out some so you can tip the front of the seat up and back to get to the connections shown in the first picture. You will want to access the white connector as well as the gray connector on the seat module. Now using a test light connected to ground you will need to test at the gray connector from the seat heater module for voltage and ground. Do not touch the yellow connector, that is for the airbag in the seat. The chart below tells you what you should find at each of the pins that you test, you will be testing using a back probe method to test the component without disconnecting it. Doing it this way should avoid needing to do any reinitializing of parts. To do back probing you can use a simple probe or even something like a sewing needle that slides into the connection from the outside and makes contact with the inner connection pin. The four connections circled in red should have battery power with the key on. The connection circled in black should be the ground circuit. To test the battery voltage with a test light connect the test light to a good ground and probe the connections. For the ground connect the test light to battery positive and see if it lights up when you probe the black wire. If they all check out then the issue is likely the controller itself. Or the wiring into the white connector C651 on the seat frame. To test there you can use the same testing methods as at the module. There should be power with the key on at the pins in red and grounds at pins 4, 9, 12 and 14. So in testing say you don't find power on pin 9 with the light green wire at the module if you then test the same wire at pin 8 in the white connector and do find it has power, there is a break in the wire between the two. Or if you don't find battery voltage at either point in testing there is a problem in that power feed between the fuse and the seat harness.

Some of this testing could be checked using a dealer level scan tool to see in the system has set any trouble codes. However that depends on the skill of the person using the tool more than just doing the physical tests.

I THINK it's internal. Meaning I think it's in the switch and not accessable. You're probably going to need to replace the switch. Does the heater work?

That is what the testing is for, the control panel doesn't use an on/off type control, it sends a signal over the CAN network to the control module telling it to activate the heater grids and how much and rarely will those fail. As all of the heaters stopped working at the same time it is something that is common to all of the pieces. The power and grounds at the control module and wiring will show if the system has the power and grounds to operate and many times the issue is in the power or ground as they are located in bad places really. Think about how we stuff things under the seats or how we get in out with snow, water, dirt on out feet and it all gets into things at that level.
The next step in testing after checking all of this is to use a scope and scan tool to look at the control signal and be sure it is getting to the control module, however it depends on the test equipment you have if you can go that far. That is why I try to go after the more common failure items first.

Hello,

There are two fuses that run the system # 30 (underhood) and # 6 (pass comp) with a relay here is the heated seat wiring diagrams so you can see how the system works and the relay and fuse locations as well. Also here are two guides to help you test the fuse and relay.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

and

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the diagrams (Below). Please let us know what you find. We are interested to see what it is.

Maybe, it would depend a lot on what scan tools they have. You would need to look at what they actually have.

Hi pynuts,

Not sure which type of bulbs is attached, 2 types.

Look for a rubber rectangular plug and pull it out. Another type is screw on plastic round button.

If the parts all tested OK then it is likely the control module under the seat.