Heated Seats Won't Stay On

My 2009 just started a problem with the heated and cooling function of both front seats.

Doesn't matter what side, driver or passenger. Doesn't matter which button - back heat, back&butt heat, or AC.
You push the button on the door and the lights come on. Most of the time you can hear the relay under the passenger seat click on.
Then 2-3 seconds later, the same relay under the pass. seat clicks off. The lights on the door are still lit though. You can push the buttons on and off as much as you want, but you'll never hear another click of the relay.

Turn the truck off and back on, and you can repeat the process. You'll get a relay click on, then 2-3 seconds later click off. Then it won't click on again at all. But the entire time the buttons and lights on the door act as if everything is working fine.


Anyone else had this?

Probably one of the heater element pads in the drivers seat is bad.

In mine, the element in the driver's side seat back was bad the first time.

The second time, it was the seat bottom element.

The seat back element seems to be the one that goes out the most, from what I've read.

Have a look at this troubleshooting video from The Seat Shop.

Pay no attention to the years he mentions in the video.

The same problem exists in all years.

From what I've seen, when that was the problem the door lights would shut off too. Mine stay on. Does that seem right? And when your driver elements were bad, did it cause the passenger side to shut off too? Or do you think I've got a bad element in both seats?

One bad element will cause the entire heated seat system to shut off (all 4 elements).  I have never heard anything about lights also going off.  They don't in mine...

Determining which side has a bad element (driver/passenger) is easy.  Determining bottom or back for a particular side is a crap shoot.  Measuring the resistance of the element doesn't often help.  You would probably need a current measurement which would require building a test harness.

IMO you get more life out of the Dorman aftermarket elements.  Buy one from eBay.    Might as well start with the back element, you might get lucky. 

On mine, one bad element shut down both seats each time.

The second time they went out I didn't realize I even had a problem until my wife told me the passenger seat heater did not work.

The first time, my driver seat started up on it's own while I was sitting on line at the bank drive thru in the middle of the summer.

At first, I thought I might have hit the seat heater button when I rolled down the window, but that wasn't the case.

The seat heater came on by itself several times after that and I began the troubleshooting process.

First time around, I had purchased two new Dorman replacement heater pads and replaced both in the driver's seat.

It was obvious the driver's side back heater was the problem, as you can see in this photo:



The second time mine failed, the new Dorman seat bottom pad went bad.

That failed pad did not burn up like the seat back pad had done.

It just quit working.

That time, the door panel lights would come on for a short period of time, then go out.

I replaced it with another Dorman unit and it has been fine for the past two seasons.

Both times, I checked the ohms and continuity of each pad and was not able to determine anything since both the good and bad showed close to the same readings.

It would appear the ohm range to trigger a failure must be quite small or the computer is looking for something else entirely, perhaps current flow rate.

Way above my pay grade to know such things.

I would assume this to be the case for most if not all seat heaters but the ones that I'm retrofitting into our vette have a thermal switch that will shut them off if they get too hot or maybe hot enough.  I'd think it's possible that if you aren't measuring an abnormal resistance reading then the switch may be shutting them off way too soon.

My butt warmer quit a couple years back, at first the light would stay on briefly and cut off then it quit coming on at all. They do cut off after they reach a certain temperature, supposed to anyway.

The light staying on with the pads not warming is possible, like others stated if one quits they should all quit. There must be some current tricking the switch to think the pads are on or a faulty switch.

I think maybe when they go bad (burnt wires) the resistance/impedance changes when it heats up.  The system detects its applying too much power, getting into a short situation, and shuts everything down.  Then the element cools down, you measure resistance, and its the same as a brand new one.  You can easily measure the in circuit live current with any old digital multimeter from radio shack.  Its just a pain to have to cut one of the wires in your harness (or build a harness with the correct connectors) to do so...    It takes less time to just use trial and error and buy some new elements.  As pointed out, when you get the element out, its often quite obvious (burn marks) when one is bad.


 

To re-cap: turning on heat OR cooling on either driver or passenger side would turn the lights on the door on. Relays under passenger seat would click on, then off after 3 seconds. Door lights would stay lit. Pushing any of the buttons would not make relays click until you turned the truck off and back on.


Had the dealership check it out. They said the seat controller module was toast and harness connecting to it was toast. Quoted $900 for a new module and go from there.

I found this YouTube video https://www.youtube.com/watch?v=bDVrnCjDEuM. Dude's Ford Expedition had the same problem I described. His wire harness to the seat controller module was toasted. Saw a comment saying someone used his method to fix their Escallade. I looked at my harness and it was a dang 100% match for what he had. Sucked it up and ordered the Ford part. http://www.ebay.com/itm/291686407821?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I can't believe it but this fixed the problem! In some of the comments of the video folks were talking about the power/ground needing to be spliced into 2 connectors. The harness has 2 unused connectors right next to the power and ground, but I'm not sure which would be the extra power and which is the extra ground. Didn't mess with it - just did a 1-1 and had 2 extras.

I hope this can help someone else with the problem.

HellHoof said:

To re-cap: turning on heat OR cooling on either driver or passenger side would turn the lights on the door on. Relays under passenger seat would click on, then off after 3 seconds. Door lights would stay lit. Pushing any of the buttons would not make relays click until you turned the truck off and back on.


Had the dealership check it out. They said the seat controller module was toast and harness connecting to it was toast. Quoted $900 for a new module and go from there.

I found this YouTube video https://www.youtube.com/watch?v=bDVrnCjDEuM. Dude's Ford Expedition had the same problem I described. His wire harness to the seat controller module was toasted. Saw a comment saying someone used his method to fix their Escallade. I looked at my harness and it was a dang 100% match for what he had. Sucked it up and ordered the Ford part. http://www.ebay.com/itm/291686407821?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I can't believe it but this fixed the problem! In some of the comments of the video folks were talking about the power/ground needing to be spliced into 2 connectors. The harness has 2 unused connectors right next to the power and ground, but I'm not sure which would be the extra power and which is the extra ground. Didn't mess with it - just did a 1-1 and had 2 extras.

I hope this can help someone else with the problem.

Click to expand...

Thanks for reporting your solution! 

Totally the problem in my '09 LTZ.

Trying to figure out how to fix it, for the long term, now.

My fix is still running strong. $40 and you won't look back

HellHoof said:

My fix is still running strong. $40 and you won't look back

Click to expand...

That's the plug and wires that you splice in? Anything to keep it from happening again and again?

https://www.amazon.com/ACDelco-15326110-Original-Equipment-Multi-Purpose/dp/B00493VYUO/ref=pd_sim_263_1?_encoding=UTF8&pd_rd_i=B00493VYUO&pd_rd_r=VCK01YP9XPEKGYRZMJET&pd_rd_w=DicLR&pd_rd_wg=0bvBH&psc=1&refRID=VCK01YP9XPEKGYRZMJET

Doing some more digging. The one comment by Jared N. on Nov 14, 2016 is interesting:

"You first separate the plastic plug by sliding the white piece out the side. Each of the wires is secured in the bottom of the plug with a catch, it's very small, you will need a small screwdriver, I used one that's for eyeglasses. You pry lightly on the catch of each connector (Each wire) and remove them one at a time. It's a bit challenging if the plug is melted. I was able to get most of them out of ours the proper way but needed to deconstruct the damaged portion to get those ones out. If your plug is melted it's usually a sign that your grounds should be checked, especially the main battery ground cable that grounds to the engine block and frame (Same cable, there's 2 ends)"

From my readings, it is a matter of too much voltage going through the single wire. The plug has 2 extra pins that are not used, and another person online had deconstructed the module and soldered the extra pins to act as secondary ground and positive leads. I didn't go that route, so, no - no reason to stop it from happening again. I'm just taking the gamble that is lasted for 7 years on the first plug and hope the second one goes for another 7.

HellHoof said:

I'm just taking the gamble that is lasted for 7 years on the first plug and hope the second one goes for another 7.

Click to expand...

So much win in that statement. I'm intrigued though by taking the plug apart. It's $7 vs $40.

I'd go the plug route. Had I known of that at the time I did mine, that would have been the route I took.

I had a bit of an emergency last week, but plan on trying to pull the plug apart soon. Once I do that, and we get to really see what we're working with, I'll post pics and let you, and everyone else, know.