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Disabling memory - drivers seat

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Probably an unpopular route here, but I was curious if there was an easy way to disable power to the memory modules on the drivers seat, rather than wire up the K72 relay.

 

I fitted a set of M5 seats a couple of years back and just wired up power and they work great. I never bothered searching for/getting a drivers memory loom and haven’t really any interest in getting the memory option working.

 

But it’s causing battery drain, as I was fully expecting. Unplugging seat solves drain but of course throws an airbag light.

 

I have to remove the drivers seat to replace the seat base foam shortly and while I’m at it I’d love if there was some sort of quick fix to permanently disable/remove the memory modules on the motors from drawing power.

 

I could go to the hassle of sourcing and fitting a K72 but a little pointless considering the memory isn’t active anyway. However still might be easiest solution to my problem.
 

All thoughts welcome!!

 

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17 hours ago, rpg said:

Probably an unpopular route here, but I was curious if there was an easy way to disable power to the memory modules on the drivers seat, rather than wire up the K72 relay.

 

I fitted a set of M5 seats a couple of years back and just wired up power and they work great. I never bothered searching for/getting a drivers memory loom and haven’t really any interest in getting the memory option working.

 

But it’s causing battery drain, as I was fully expecting. Unplugging seat solves drain but of course throws an airbag light.

 

I have to remove the drivers seat to replace the seat base foam shortly and while I’m at it I’d love if there was some sort of quick fix to permanently disable/remove the memory modules on the motors from drawing power.

 

I could go to the hassle of sourcing and fitting a K72 but a little pointless considering the memory isn’t active anyway. However still might be easiest solution to my problem.
 

All thoughts welcome!!

 

 

Have you tried coding it out the ZKE?

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Where from did you connect the voltage supply to seats? If you don't want to install the sleep mode relay one quite easy alternative is to take the supply from fuse box on some switched (Terminal R / ignition pos. 1 or Terminal 15 / ignition pos.2) empty fuse location.

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Of course, makes complete sense. For the driver’s seat I wired directly to fuse board above battery in the boot (2.5mm cable). I chose one of the empty slots, and replaced the OEM fuse with a 30A midi fuse. See attached image for exact location.

 

Obviously I’m quite close to the standard rear fuse panel also, but I don’t believe any of these fuses are switched?


I wonder is my best option to re-route the positive cable the other direction up behind the dash to a switched fuse. The negative is grounded underneath the seat.

 

Thanks for replies. RE: coding suggestion, I haven’t needed to code anything. I went from manual seats to simply electric seats, I just provided power. 

BD166870-A834-4B01-90D9-4BF78BC65B9B.jpeg

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1 hour ago, rpg said:

Of course, makes complete sense. For the driver’s seat I wired directly to fuse board above battery in the boot (2.5mm cable). I chose one of the empty slots, and replaced the OEM fuse with a 30A midi fuse. See attached image for exact location.

 

Obviously I’m quite close to the standard rear fuse panel also, but I don’t believe any of these fuses are switched?


I wonder is my best option to re-route the positive cable the other direction up behind the dash to a switched fuse. The negative is grounded underneath the seat.

 

Thanks for replies. RE: coding suggestion, I haven’t needed to code anything. I went from manual seats to simply electric seats, I just provided power. 

BD166870-A834-4B01-90D9-4BF78BC65B9B.jpeg

 

Once you grab power supply from the correct source, you need to code the car/key memory behavior to avoid the ZKE to prevent the sleep mode.

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Also adding the SA change in NCS Expert before recoding the IKE, EWS, DSC and ZKE to the new SA. so you have the features correctly enabled, and then edit your preferences either by NCS Expert + NCS Dummy, or PASoft's BMW Scanner, or DIS.

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Thanks for the input, but I don’t think any coding is necessary? It’s just positive and negative feeds required. No features are enabled, I simply want seat power that’s all.

 

Can’t seem to find a switched fuse capable of a 30A load? I know fuse 19 is free and switched but it’s only 5A rated. That’s asking for trouble, probably only a thin wire feed, definitely not 2.5mm anyway I wouldn’t say.

 

I even thought about adding in a little rocker switch on the positive cable, and turn it on when I need to adjust seat, but I don’t really like the idea.

 

Maybe K72 is the only decent solution to doing this after all?

Edited by rpg

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22 minutes ago, rpg said:

Thanks for the input, but I don’t think any coding is necessary? It’s just positive and negative feeds required. No features are enabled, I simply want seat power that’s all.

 

Can’t seem to find a switched fuse capable of a 30A load? I know fuse 19 is free and switched but it’s only 5A rated. That’s asking for trouble, probably only a thin wire feed, definitely not 2.5mm anyway I wouldn’t say.

 

I even thought about adding in a little rocker switch on the positive cable, and turn it on when I need to adjust seat, but I don’t really like the idea.

 

Maybe K72 is the only decent solution to doing this after all?

Of course, you could just install a battery behind them seats and have a friend touching the cables on the terminals while you adjust the seat and be done with all the unneccesary complications. 

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No coding is required. I found the GM is not that fussy about coding anyway.

 

Why not just add a relay to switch the 30A connection to the seat using the switched 12v you have available.

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On 01/08/2021 at 03:08, rpg said:

Of course, makes complete sense. For the driver’s seat I wired directly to fuse board above battery in the boot (2.5mm cable). I chose one of the empty slots, and replaced the OEM fuse with a 30A midi fuse. See attached image for exact location.

 

Obviously I’m quite close to the standard rear fuse panel also, but I don’t believe any of these fuses are switched?


I wonder is my best option to re-route the positive cable the other direction up behind the dash to a switched fuse. The negative is grounded underneath the seat.

 

Thanks for replies. RE: coding suggestion, I haven’t needed to code anything. I went from manual seats to simply electric seats, I just provided power. 

 

On rear fuse panel all are permanently live (Terminal 30). On front fuse panel there are usually several empty slots. The supply rail side connector is already there. Measure (or check from wiring diagram) which of those empty connectors is switched. Then add fuse connector on the other side. 

61130007440

 

image.png.539696c87cdc5f7963493396b988254e.png

Edited by Clavurion

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Thanks Johan & Clavurion for the replies, very helpful.

 

I think I'm going to go with both suggestions. I'll pick up a 4-pin SPNO 12v relay with a 30A contact rating (pictured below), retain my clean +12v from the rear fuse board and wire relay in between. I'll then use one of those double leaf spring contacts pictured above and wire into back of front fuse board (most likely F19 once I confirm it's switched) - this feed will be the 'make & break' on the relay. So I only have to really route 1 cable from front fuse box to under driver's seat, and no tapping will be required.

 

This solution saves me doing 2 things that aren't necessary; finding a K72 for a reasonable cost (they're not as easy to come by as they used to be), and splicing into pin 19 on X254/GM.

 

It's as good as I'm going to get without doing anything irreversible. Might measure parasitic drain before and after too, out of curiosity. Will report back with results. Thanks again.

 

 

 

relay.jpg

Edited by rpg

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this will in effect not require the memory to be coded off "properly", and most likely will cure the parasitic drain. Also serves the very good purpose of leaving things unaltered should you want to go back for some reason. It's the analogic solution that makes things easy but's not shabby or crude.

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14 hours ago, Clavurion said:

Fuse F19 is Terminal 15 = ignition switch pos. 2.


Thanks for heads up. Ideally I’d prefer Terminal R. I’ve F45 free also; a quick check of WDS indicates terminal R. Will verify with multimeter just in case.

 

19 hours ago, jicaino said:

this will in effect not require the memory to be coded off "properly", and most likely will cure the parasitic drain. Also serves the very good purpose of leaving things unaltered should you want to go back for some reason. It's the analogic solution that makes things easy but's not shabby or crude.


That’s the idea. However, memory was never coded “in”, so nothing to code “out”. I went from manual cloth seats to electric M5 seats. I simply provided power and ground independently, I never even wired into P-bus or added SA code. For all intents and purposes, the car has no idea they’re there!

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2 hours ago, rpg said:

That’s the idea. However, memory was never coded “in”, so nothing to code “out”. I went from manual cloth seats to electric M5 seats. I simply provided power and ground independently, I never even wired into P-bus or added SA code. For all intents and purposes, the car has no idea they’re there!

If I had a dime for every time I've made a fool out of myself :P

 

 

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