Z4M Seats Installed — Strange Seat Memory Error (Hall Sensor Short to Batt+)

[LSB4Me]

Happy New Year, Gents.

At the end of 2024 (12/31), I installed a pair of e85 Z4M seats in my e46. For those of you that don’t know, these are a neat plug-and-play option for us that don’t enjoy the stock sofas. The seats look awesome, sit lower and just bolted in, after I swapped the seatbelt receivers over.

As for the plug-and-play aspect, the seat heaters work and the power controls operate the seat correctly. However, I am not able to use the memory settings to recall saved seat positions.

Reading the error code yields: “Power supply hall sensor, short to batt+”. Oddly enough, the e46 seat underside seems to differ from these Z4M seats in that the e46 seats have long flat connectors that appear to service the hall sensors, if I was a guessing man.

NOTE: The red “M” for saving positions does light up and pressing the 1, 2, 3 buttons moves the side mirrors to their saved positions. The seat doesn’t move though.

Also of note, the driver seat moves when using the controls in 3 second bursts and I swear Memory Position 1 worked the first time I pressed it after install and the motors ran for more than a burst. The passenger seat moves consistently whilst the toggle lever is pressed.

I have removed the seats and checked closely for broken wires. Nothing. I’ve cleared the error code. It comes right
back.

SOLVED: Problem was a faulty switch control module. Swapped over the module from the e46 seat and, like magic, the memory presets work.

Thanks to all who chimed in. You are legends.

[LSB4Me]

Update: I checked all the connections and wires from start to finish. They look good.

New Clue #1: The power seat controls require two presses in order to move the seat. Doesn’t matter which direction or function. First press just clicks. Release and press a second time for movement.

New Clue #2: The seat moves in bursts no which which lever or direction is pressed. Seat back, seat base, tilt. They all move for 2-3 seconds then stop. Double pressing the switch moves them again. This tells me it’s something central. Perhaps the switch panel itself?

Feels like these two clues might get this moving, no pun intended. Any thoughts or suggestions?

[I M Legend]

To be clear, other folks have successfully swapped in these seats and they work fine or are you the first to do it and coming up with this memory issue?

[nextelbuddy]

It honest. Sounds like the seat control module is bad. And maybe worth your time just to swap out the seat module with one from your old seats

[Slideways]

Both E85/6 and E46 have a Control Module 5 (GM5), but the part numbers, current and superseded, appear to be different.

[jvit27]

Never had this issue with my Z4M seats. The only barrier of swapping them was the passenger occupancy sensor (which there are three obvious solutions)

Tip: once you DO get them working, set a Memory button to maximum ingress/egress for the rear seat. You can crunch the headrest into the headliner or break the mirror in the sun visor if you go too far. Also makes it easier than having to manually hold and watch each time since they do move a bit slow..

Did you do impulse cloth centers? Cool!

[LSB4Me]

Never had this issue with my Z4M seats. The only barrier of swapping them was the passenger occupancy sensor (which there are three obvious solutions)

Tip: once you DO get them working, set a Memory button to maximum ingress/egress for the rear seat. You can crunch the headrest into the headliner or break the mirror in the sun visor if you go too far. Also makes it easier than having to manually hold and watch each time since they do move a bit slow..

Did you do impulse cloth centers? Cool!

Thanks, JVT! This gives me hope. Roger that re setting maximum positions. I found this issue when trying to set the max front setting so the woofer could access the rear seats. That’s how my memory was set on my stock seats and he knows/knew the drill.

What is weird is that the preset buttons move the mirrors to their set positions, but the seat doesn't move. This was my first big clue that something was amiss.

What year is your car and do you know which year your seats came from? My car is an 04 and the seats came from an 06, I'm told. A photo of the underside of your driver seat would be AWESOME.

And yes, I bought some spare rear sets in Impulse and had my upholstery shop sew in the cloth to match the interior.

[LSB4Me]

It honest. Sounds like the seat control module is bad. And maybe worth your time just to swap out the seat module with one from your old seats

Good call and agreed. The problems suggest one centralized problem--I was zero-ing in on the switch. Not sure if it is the same between the e46 and e85, but it appears to be an easy swap, if so.

https://www.pelicanparts.com/techarticles/BMW_Z4M/99-INTERIOR-Seat_Switch_Replacement/99-INTERIOR-Seat_Switch_Replacement.htm

[LSB4Me]

UPDATE: Problem solved. I have edited the original post in hopes of helping others. For those of you considering this swap, I only have great things to say about the support and seating position. This is how the car should have come.

You guys are legends. Thanks very much for the input and for helping me troubleshoot.

Attached are a few additional photos for fun.

[Maxhouse97]

Question on the benefits of this swap - are you saving that much weight or is it more for aesthetics? Also these fold in the same way as stock seats?

[LSB4Me]

Question on the benefits of this swap - are you saving that much weight or is it more for aesthetics? Also these fold in the same way as stock seats?

I was never a fan of the stock seats. For me, you sit on them, not in them, and they lack upper shoulder support that I like/need. Additionally, these seat you much lower in the car (my head would hit the visor in the stockers) and are the preferred shape for my body type.

I considered going Sportster (had the M Perf variant in my e92) or Nogaro, but really didn’t want to cobble together aftermarket mounts and power switch controls. Plug and play is my jam. Hence the M Perf seats vs regular Sportsters.

Additionally:

They have better bolstering.
They are lighter, but not by more than 10lbs.
They cost less than the aftermarket options.
Their seat heaters work.

[Bry5on]

I was never a fan of the stock seats. For me, you sit on them, not in them, and they lack upper shoulder support that I like/need. Additionally, these seat you much lower in the car (my head would hit the visor in the stockers) and are the preferred shape for my body type.

I considered going Sportster (had the M Perf variant in my e92) or Nogaro, but really didn’t want to cobble together aftermarket mounts and power switch controls. Plug and play is my jam. Hence the M Perf seats vs regular Sportsters.

Additionally:

They have better bolstering.
They are lighter, but not by more than 10lbs.
They cost less than the aftermarket options.
Their seat heaters work.

About how much lower are they than stock? This seems very appealing for us taller guys. I have sportsters now and was able to get them 1/4” lower using custom brackets. Also using e39 heated seat elements. Would love to sit .75” lower still but there’s just no room.

[jvit27]

Thanks, JVT! This gives me hope. Roger that re setting maximum positions. I found this issue when trying to set the max front setting so the woofer could access the rear seats. That’s how my memory was set on my stock seats and he knows/knew the drill.

What is weird is that the preset buttons move the mirrors to their set positions, but the seat doesn't move. This was my first big clue that something was amiss.

What year is your car and do you know which year your seats came from? My car is an 04 and the seats came from an 06, I'm told. A photo of the underside of your driver seat would be AWESOME.

And yes, I bought some spare rear sets in Impulse and had my upholstery shop sew in the cloth to match the interior.

Late to this but saw/glad you solved it. It would be a few weeks before I would be able to get some upskirt pics of the seats anyways. My car is an 04 also but I've long forgotten what MY the seats are...

I too was set on Sportsters but landed on the same tradeoffs. The car is no longer my daily though so I plan on moving on from the Z4M seats to something more aggressive this season.

About how much lower are they than stock? This seems very appealing for us taller guys. I have sportsters now and was able to get them 1/4” lower using custom brackets. Also using e39 heated seat elements. Would love to sit .75” lower still but there’s just no room.

I'd say they drop you about an inch lower. I still have to hit you up to meet at a C&C and check out your wagon + slon! Life got in the way last year, but we can discuss seats soon.

Question on the benefits of this swap - are you saving that much weight or is it more for aesthetics? Also these fold in the same way as stock seats?

Negligible weight savings, they are just more comfortable than the stock seats. Aesthetics were just a big bonus. Downside is they don't latch forward like stock seats so you forfeit some access clearance to the rear seats.

I actually had CSL seats as well but all things considered, Z4M were the ones I chose to keep.

[Bry5on]

Late to this but saw/glad you solved it. It would be a few weeks before I would be able to get some upskirt pics of the seats anyways. My car is an 04 also but I've long forgotten what MY the seats are...

I too was set on Sportsters but landed on the same tradeoffs. The car is no longer my daily though so I plan on moving on from the Z4M seats to something more aggressive this season.



I'd say they drop you about an inch lower. I still have to hit you up to meet at a C&C and check out your wagon + slon! Life got in the way last year, but we can discuss seats soon.



Negligible weight savings, they are just more comfortable than the stock seats. Aesthetics were just a big bonus. Downside is they don't latch forward like stock seats so you forfeit some access clearance to the rear seats.

I actually had CSL seats as well but all things considered, Z4M were the ones I chose to keep.

Yes please, I’d love to get a seat in them!