Heated Seat Troubleshooting

[MM03MOK]

Has anyone done any troubleshooting on heated seats not working, without using the allegedly required "restraint system diagnostic tool" (as stated in the manual.) The lights work on the switch but the driver seat doesn't seem to warm any.

[ImpalaSlayer]

just in time for winter! doesnt that just suck. sorry but no i have no idea.

[Zack]

Prolly a stupid relay somewhere

[FordNut]

Are both elements not working? On both low and high?

If both the base pad and lumbar elements are not working it's probably the controller. It's mounted on the bottom of the seat. If one or the other of the elements is working it's probably the element. Since the passenger side is working it's probably not a power distribution problem since both sides get their power from the same source.

Maybe you can unplug and re-connect the electrical connector under the seat and get it working if it's a bad connection.

[MM03MOK]

All the lights light up on the switches but neither seat, lumbar or base, get warm on high or low. I posted before Bob took it for a ride and checked both seats.

[FordNut]

Check Fuse 3 in the main fuse box next to the battery. It should be a 25A.

Your first post wasn't clear that both sides were bad, you just mentioned the driver's side.

[MM03MOK]

Check Fuse 3 in the main fuse box next to the battery. It should be a 25A.

Your first post wasn't clear that both sides were bad, you just mentioned the driver's side.Thanks. I'm only ever in the driver's seat! :D

[MERCMAN]

Heated seats?? We don't need no stinkin' heated seats.:poke:

[jonroe]

Just happened to me too this week when the outside temp hit 17 on Thursday morning. So far I only know that the whole driver's seat stays cold. Have not checked the passenger side. This sucks. I would say this is a fairly unacceptable failure in quality. My wife's Acura heated seats have been fool proof for 6.5 years.

[jonroe]

I checked fuses - no problem. Without actually sitting in it, I think the passenger seat heaters work. So, I guess it must be the control module under my seat. I fiddled with it but no help. Alas, back to the dealer for a stupid problem. Jon

[04MEMA]

Mine's acting up too - any news on the fix???

[jonroe]

I was at the Ford dealer last weekend and asked about the heated seat controller under the seat. He said it's only $55. I might gamble and just change it given that my ESP warrantee is going to cost me $100 deductible anyway. I think it's my controller as fuses are fine, both driver seat elements are not working, and the passenger seat works fine. It's got to be the controller.

[Dragcity]

Are you guys sure the seats heat with nobodys bottom in it. I have turned mine on and let sit for 10 minutes with no heat. Then when I sit down, it will begin to warm.

Could this be the issue...?

[04MEMA]

I just checked - and the manual says that you must de-power the seats air bag SRS system before servicing the heated seat module...

One thing though - assuming the modules are the same on both sides perhaps one could just swap them (assuming the pass seat heater works) to verify that as the fix.

[FordNut]

You pretty much have to remove the seat to get the control module out. And when you disconnect them, you have powered down the airbags!

[04MEMA]

You pretty much have to remove the seat to get the control module out. And when you disconnect them, you have powered down the airbags!

There's more to it than that according to the Ford Service Manual. Perhaps that would work - but you might be running more risk of triggering the bag if the Ford procedure is not followed.

[FordNut]

I've had them in & out numerous times. If you wanna make it more difficult, go ahead.

[04MEMA]

I just didn't want the air bag to blow up in someones face. Knowing what the Ford Service Manual requires I couldn't in good conscience recommend otherwise. Know what I mean?

[FordNut]

I just didn't want the air bag to blow up in someones face. Knowing what the Ford Service Manual requires I couldn't in good conscience recommend otherwise. Know what I mean?

I realize that, I was just saying my experience proves some of the manual's recommendations are unnecessary. I have a manual too, and I read the instructions. I thought, what a pain.

Then I looked at junkyards and parted out cars and found that they just pull the plug with no problems. I watched them pull the driver's seat at the Ford service dept to replace my seat cover and guess what? They did the same thing. Just unplug the connectors and remove the bolts, then pull the seat out.

[04MEMA]

Hey - it's all good and I appreciate you sharing your experience.

[Chachacharlie]

I know it's an old thread, but I'm just now having the identical problem. Neither seat heats at all. Switches light up, all fuses OK.

Did anyone replace the module(s), and with what result? Or was there another solution?

BTW, does each front seat have it's own module, or just one controlling both?

Many thanks for your help. I have a 2004 Mercury Marauder, dark toreador red, light grey seats, 107K relatively trouble free miles.

[RF Overlord]

Each seat has its own module. Since neither one works, check F1.3 (25A) in the Battery Junction Box. That fuse supplies power to both modules.

Unfortunately, the more common failure is the heating grid. You need to take the seat covers off to replace.

[champ1173]

Alright, I gotta ask a question now. Both my seat heat up wonderfully, but they both don't light up. They light up telling me they're working, (Orange light) though nothing else. Every once in awhile the driver side lights up, or blinks, but not the passenger side. Is that just a fuse? Or is this something I need to take apart, find the LED, and weld a wire or something back on?

[MM2004]

Alright, I gotta ask a question now. Both my seat heat up wonderfully, but they both don't light up. They light up telling me they're working, (Orange light) though nothing else. Every once in awhile the driver side lights up, or blinks, but not the passenger side. Is that just a fuse? Or is this something I need to take apart, find the LED, and weld a wire or something back on?

Common problem with the switch, and will need to be replaced. Mine very early on suffered from the lights in the switches blinking, as well as many others on the site.

I believe the switch is about $35.00 if my memory serves me correctly?

;)

Mike.

[champ1173]

Common problem with the switch, and will need to be replaced. Mine very early on suffered from the lights in the switches blinking, as well as many others on the site.

I believe the switch is about $35.00 if my memory serves me correctly?

;)

Mike.

Thanks! I'd rather just buy a new one then go through the hassle of taking it apart. My front two switches for the windows wont light up, on the drivers side door panel. Another common problem! Well, I read a write up about how to fix them, and it seemed like a lot of work, just to get the LED to work. Then I saw on ebay that it was only $20 to get the whole Master Control Switch. Un-plug the old one, Plug in the new one, and it works! Much easier to do.

[Chachacharlie]

Each seat has its own module. Since neither one works, check F1.3 (25A) in the Battery Junction Box. That fuse supplies power to both modules.

Unfortunately, the more common failure is the heating grid. You need to take the seat covers off to replace.

A: I checked that fuse as well as the two related fuses (for lights in the switch and the control module) in the box next to the brake pedal. All are OK.

B: If only one seat didn't work, I might suspect a bad grid. But both seats went out, and there has been no one sitting on the passenger side for 99%+ of the car's life.

[RF Overlord]

I suppose you COULD have 2 failed modules...

Can you unplug the module connector and at least verify you have 12V?

It's a 12-pin, and you want pins 6 & 7...YE/LB and WT/LB

[Chachacharlie]

Had mechanic test driver's seat heater grid continuity - found 'open circuit' indicating a bad grid. I believe he also checked voltage re. the previous post. He said the passenger seat heater was working, though it didn't feel warm to me.

Had grid replaced, and took the opportunity for auto upholstery shop to rebuild some of the cushioning. Also replaced seat & back covers with new matching flint grey factory leather I had (fortuitously) bought back in '05 or '06. (I keep cars a long time, and I knew I was hard on driver's seats.)

I still can't feel any real warmth coming from either seat, even on 'high'. Is my memory faulty? I seem to remember the seats would get noticeably warm within a minute or so, even on the 'low' setting. What's your experience?

Also, re. the "control modules": do these just function only as on-off relays, or do they actually vary (modulate) the current going to the grids? If the latter, maybe it's worth replacing one.

Don't know what I'll do next. Maybe it's time to admit defeat and that some stuff just stops working on 10 year old cars.

[Mr. Man]

Seats should definitely get warm. If you can't feel the heat then the seat is not working or you're not. ;)

[ctrlraven]

I need to buy some new switches. Passenger side has always blinked since I first got the car and past year or so the driver's side I have to press 3-10 times to just get to turn on.

[Mr. Man]

I need to buy some new switches. Passenger side has always blinked since I first got the car and past year or so the driver's side I have to press 3-10 times to just get to turn on.Have you tried resoldering them?

[ctrlraven]

Have you tried resoldering them?
No would rather just replace them.

[Chachacharlie]

Testing indicated heating element 'open circuit', which was confirmed after the element was removed from the seat. New element was checked for continuity before installation.

Still no heat. Voltages presenting to the plug are on spec, so it's not the module.

My mechanic now thinks there may be a break in one (or more) of the six wires in the flexible under-seat wiring harness that feeds the element - that's six out of the dozens in the same harness that goes to the seat motors, lumbar support, etc.

A new harness is almost certainly cost prohibitive, so he wants to remove the seat again, test for the bad wire or wires, and splice or re-wire around them.

Does this sound reasonable? Any thoughts or similar experiences?

BTW, several of earliest posts in this thread mentioned heat in the lumbar area. I was told there is no element in the seat back, only in the seat bottom, as suggested by the icons on the control button. (2004 late production Marauder). Which is it?

Thanks again for any advice.