Heated/Cooled Seats mystery

[Cobra Jet]

Here's what they ended up changing on mine...

Interesting so now there’s a JU5Z module that may be the newest Ford part #?

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[Ginger1]

Interesting so now there’s a JU5Z module that may be the newest Ford part #?

Could be. I suspect this module keeps getting revised as more failures work their way through the pipeline.

 

[Elp_jc]

Interesting so now there’s a JU5Z module that may be the newest Ford part #?

My car has a similar one: JU5T-14C708-BL, so wonder what the darn difference is. Mine is a 'T' vs 'Z', and 'BL' vs 'S'. Wonder if whoever posted that has power heated and cooled seats. But at least there's another 'J' module, so guess my car has the right one. Nobody responded which passenger connector to check, since there's no module on the passenger seat on my car. So guess I'm good then .

 

[Bit_the_Bullitt]

I've actually been to a dealer in November of 2020, just before Thanksgiving. They said they ordered new modules for driver's cooled seats, but they also need to replace a bracket, which hasn't come in yet (4 fkn months later), so they don't want to dig into the seats yet.

By the way - anyone has a HORRIBLE rattle in their passenger seat when nobody's sitting in it? I can distinctly feel this plastic "strap" on the back of it that rattles into the leather of the seat and makes a loud, annoying sound with each bump in the road I hit.
I know it's this because I've put my hand to it to keep it tight/stop it from rattling and no noise.

ANYONE else? Drives me nuts.

 

[tapan]

Bumping an old thread instead of creating a new one...

I have a 2017 Mustang GT premium (build date is April 2017)

My driver's heated seat is not working anymore. Driver's cooled seats and passenger heat/cool seats work fine.

I started experiencing this issue a few days ago. Maybe it's a coincidence (or caused by?), but I did use the built in cigarette lighter outlet to power the supplied air compressor for 5 minutes.

Anyhow, when I turn on driver's heated seat (after the car first starts up), I hear the relay click, blower fan kicks in for 10 seconds (precisely one cycle), relay clicks again, and blower fan turns off. At this point, no matter if I select the driver's heated or cooled seats, the lights stay on but there is no more relay clicking - unless I turn off and on the car again. The driver's cooled seats work fine, but I have to make sure to select that first after turning on the car (it can't be followed after selecting heat).

Passenger side works perfectly fine.

I disconnected and reconnected the battery - no luck.

I checked out the harness and the module connector (underneath the passenger seat), and I am not seeing any melted pins. I haven't checked the fuses but I assume they are fine as the relay works perfectly for the passenger side heating/cooling. I do have the revised harness with 12 wires (instead of the 11 wire one which seems to melt)

I looked at the module sticker and as @JohnDoe_5oh stated, I have the exact same (old/wrong for MY2015) module.

Btw @JohnDoe_5oh mad kudos for the impressive troubleshooting in your first post! Just wanted to get some opinions on my situation:

1) What do you think the culprit is here? Relay/Fuses/Module/Heat element/Blower fan
2) I assume there is only one module under the passenger seat that controls the driver seat as well right? I couldn't find anything underneath the driver's seat
3) If it is a faulty module, I will be buying the BU5Z-14C724-A module. Do I need to disconnect the battery for this?
4) Does the new module need to be programmed or is it plug and play?

Any insights and thoughts would be greatly appreciated. Thanks!

 

[ice445]

Bumping an old thread instead of creating a new one...

I have a 2017 Mustang GT premium (build date is April 2017)

My driver's heated seat is not working anymore. Driver's cooled seats and passenger heat/cool seats work fine.

I started experiencing this issue a few days ago. Maybe it's a coincidence (or caused by?), but I did use the built in cigarette lighter outlet to power the supplied air compressor for 5 minutes.

Anyhow, when I turn on driver's heated seat (after the car first starts up), I hear the relay click, blower fan kicks in for 10 seconds (precisely one cycle), relay clicks again, and blower fan turns off. At this point, no matter if I select the driver's heated or cooled seats, the lights stay on but there is no more relay clicking - unless I turn off and on the car again. The driver's cooled seats work fine, but I have to make sure to select that first after turning on the car (it can't be followed after selecting heat).

Passenger side works perfectly fine.

I disconnected and reconnected the battery - no luck.

I checked out the harness and the module connector (underneath the passenger seat), and I am not seeing any melted pins. I haven't checked the fuses but I assume they are fine as the relay works perfectly for the passenger side heating/cooling. I do have the revised harness with 12 wires (instead of the 11 wire one which seems to melt)

I looked at the module sticker and as @JohnDoe_5oh stated, I have the exact same (old/wrong for MY2015) module.

Btw @JohnDoe_5oh mad kudos for the impressive troubleshooting in your first post! Just wanted to get some opinions on my situation:

1) What do you think the culprit is here? Relay/Fuses/Module/Heat element/Blower fan
2) I assume there is only one module under the passenger seat that controls the driver seat as well right? I couldn't find anything underneath the driver's seat
3) If it is a faulty module, I will be buying the BU5Z-14C724-A module. Do I need to disconnect the battery for this?
4) Does the new module need to be programmed or is it plug and play?

Any insights and thoughts would be greatly appreciated. Thanks!

If it was always working and now it isn't, I'd blame the heater element in the seat first.

 

[tapan]

If it was always working and now it isn't, I'd blame the heater element in the seat first.

Makes sense but with that same logic, can't other parts, especially the module, be blamed too (just thinking out loud)? As all Mustangs seat heating/cooling must have functioned properly from the factory. It must have gone faulty at some point during the ownership.

Unfortunately my OBD2 reader is fairly basic and won't read the complex codes. I called the dealer and they are quoting $150 diagnostic fees (Canadian) as my car is out of warranty. I won't be surprised if the total bill comes close to $1,000 with parts and labor Hence I am trying to figure out cost effective solutions that don't rely on a dealer.

 

[ice445]

Makes sense but with that same logic, can't other parts, especially the module, be blamed too (just thinking out loud)? As all Mustangs seat heating/cooling must have functioned properly from the factory. It must have gone faulty at some point during the ownership.

Unfortunately my OBD2 reader is fairly basic and won't read the complex codes. I called the dealer and they are quoting $150 diagnostic fees (Canadian) as my car is out of warranty. I won't be surprised if the total bill comes close to $1,000 with parts and labor Hence I am trying to figure out cost effective solutions that don't rely on a dealer.

Sure, it could be the module. I'm not saying it's impossible. Now that I read your symptoms again it does sound more like a Module issue, since I assumed it was just heat that wasn't working, not that you couldn't switch between the two.

 

[tapan]

Awesome thanks! That's more inspiring as I have enough skill to replace the module, but not enough to rip apart a seat

At the moment, it's just the driver's heat that isn't functional. But what also makes me lean towards the module is the inability to switch to cooling after heat stops working. Also, the blower fans are most definitely not the culprit as they work perfectly with cooled seats (both sides) and it's the same blower fans that work with heated seats as well.

So it's either the module or the heated seat element. I just ordered the module and it's supposed to arrive next week.

1) Do I need to disconnect the battery to replace the module?
2) Does the module need to be programmed or is it plug and play?

Thanks!

 

[Cobra Jet]

Awesome thanks! That's more inspiring as I have enough skill to replace the module, but not enough to rip apart a seat

At the moment, it's just the driver's heat that isn't functional. But what also makes me lean towards the module is the inability to switch to cooling after heat stops working. Also, the blower fans are most definitely not the culprit as they work perfectly with cooled seats (both sides) and it's the same blower fans that work with heated seats as well.

So it's either the module or the heated seat element. I just ordered the module and it's supposed to arrive next week.

1) Do I need to disconnect the battery to replace the module?
2) Does the module need to be programmed or is it plug and play?

Thanks!

Anytime working with anything electrical in any vehicle, always disconnect the battery. I know some folks don’t or won’t and say not to worry, but with these newer cars being loaded with electronics and tech, definitley disconnect to be 100% safe.

The module should be plug and play.

 

[pyrophilus]

The module should be plug and play.

I had exact same symptoms in my 17 EB, and the dealer replaced "a module" under warranty.

If you turn on the heat, and you hear the relay click on, and then 10 sec later, the relay clicks off and you get nothing, instead of turning the engine off and then on again, turn the driver's heat switch to off, wait like 30-60 sec (engine still running), and then try turning the heat back on. If the relay clicks again (and then goes through the same thing, 10 sec later relay clicks off), it is a faulty module.

When I had my problem, it was also only the driver's heat that went dead, the cooling worked (not really, i had the cooling that didn't vent the heat problem as well, but at least the peltier and the blowers were, "working"). Both heat and cooling for passenger side were working.

Please report back after you replace your module.

 

[tapan]

Anytime working with anything electrical in any vehicle, always disconnect the battery. I know some folks don’t or won’t and say not to worry, but with these newer cars being loaded with electronics and tech, definitley disconnect to be 100% safe.

The module should be plug and play.

Agree, rather play it safe!

 

[tapan]

The module should be plug and play.

I had exact same symptoms in my 17 EB, and the dealer replaced "a module" under warranty.

If you turn on the heat, and you hear the relay click on, and then 10 sec later, the relay clicks off and you get nothing, instead of turning the engine off and then on again, turn the driver's heat switch to off, wait like 30-60 sec (engine still running), and then try turning the heat back on. If the relay clicks again (and then goes through the same thing, 10 sec later relay clicks off), it is a faulty module.

When I had my problem, it was also only the driver's heat that went dead, the cooling worked (not really, i had the cooling that didn't vent the heat problem as well, but at least the peltier and the blowers were, "working"). Both heat and cooling for passenger side were working.

Please report back after you replace your module.

Will update once I install the new module. It's expected to arrive early next week.

I am having the exact same symptoms as yours (driver's heated seat) except for the 30-60 second wait. For me, once the relay clicks the second time, this cycle can't be repeated unless I restart the engine. Does it still sound like a module issue or something else?

Driver's cooled seat works just fine, I have to make sure to select that first after the engine turns on. If I select the heat, wait for the 10 second cycle to finish, and then select cooled seat, nothing happens unless I restart the engine.

Passenger side cooled and heated seats work perfectly fine.

 

[pyrophilus]

Will update once I install the new module. It's expected to arrive early next week.

I am having the exact same symptoms as yours (driver's heated seat) except for the 30-60 second wait. For me, once the relay clicks the second time, this cycle can't be repeated unless I restart the engine. Does it still sound like a module issue or something else?

Driver's cooled seat works just fine, I have to make sure to select that first after the engine turns on. If I select the heat, wait for the 10 second cycle to finish, and then select cooled seat, nothing happens unless I restart the engine.

Passenger side cooled and heated seats work perfectly fine.

Mine is exact same symptom as yours, including the 10 sec between first and second click. But... if you wait 30-60sec AFTER the second click, it seems like the system resets (like restarting the engine). The service tech was the one that discovered that it resets after a minute.

 

[tapan]

Mine is exact same symptom as yours, including the 10 sec between first and second click. But... if you wait 30-60sec AFTER the second click, it seems like the system resets (like restarting the engine). The service tech was the one that discovered that it resets after a minute.

Gotcha, I don't believe mine resets after 30-60 seconds as I have tried it with minutes apart. Fingers crossed it's the module! (it's the easiest to replace DIY).

Are you sure you had the heat/cooling module replaced or the fan blower module/assembly?

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