Rear view mirror key receiver not working

[poortomsacold]

Hello all

So I have just gotten back from BMW to get my new remote key coded with the car - sadly it only came with a basic spare key when I bought it last year (does nothing except start the car, manually locks the doors with the added bonus of a tiny LED light!).

Anyway they couldn’t code the key to the car as the receiver is apparently not working. They have said it needs a new mirror where I have read the receiver is located. That part is on massive back order and stupidly expensive.

I have checked the relevant fuse (which I’m pretty certain is fuse 30, 7.5A) which is fine, but the rear view mirror has no lights on at any time.

I’ve not taken the mirror apart to make sure it’s all connected internally, but am not sure if that is the next logical step to take in diagnosing the latest problem?

I should add that the alarm is not activating when I lock the car with the key (no idea if it should, or indeed if it does as thinking about it the light in the mirror doesn’t work), so not sure if this is another issue or all connected.

Any ideas? If it needs a new mirror are these just plug and play and, if so, would I be able to code the key myself without yet another trip to BMW?

Thanks!

 

[smorris_12]

The mirrors are generic and just act as a receiver. The GM5 module (IIRC) handles the actual security.

 

[enuff_zed]

The mirrors are generic and just act as a receiver. The GM5 module (IIRC) handles the actual security.

Could try the central locking button behind the gear levr? If that doesn't work it's another vote for the GM5.
Of course you could replace the GM5 but you will still need then to get remote keys coded to it.
Not sure where you start if I'm honest?
There are people who will cut a new key for you, from the one you have, but my knowledge is limited as to how that would then be linked to the car and a potential new GM5?

 

[poortomsacold]

All remote locking ses to be operating correctly - both from the key and also the lock button behind the handbrake so I'm not sure it's a GM5 issue.

BMW said they diagnosed it to be the receiver as they gave me the part number for a new mirror, so I'm thinking that may be correct,. especially as I have no working lights on the mirror at all.

So I'm hoping a replacement mirror could fix the issue, but who knows with these cars....

 

[colb]

The receiver is inside the clowns nose on the bottom of the mirror, since you have no lights on the mirror just check if its getting power to it, absence of power may be the cause. If you lock the vehicle using the key in the door the alarm is not set, it will only set if the locking button on the key is used. Handy to know that if you suffer from false alarm activations albeit the car won't be protected but the doors will be locked.
The following methods can be used to sync keys when you have a working receiver
BMW Z4 - Key Remote Programming

Three methods to try:

Method 1:

1. Working from within the vehicle and with the doors shut

2. Turn ignition to position 1 and back to off within 5 seconds.

3. Remove the key from ignition and press and hold the unlock button for 15 seconds during this time press the key lock button 3 times within 5 seconds.

4. Release both buttons.

5. Doors will lock and unlock to show correct programming has occurred.



Method 2:

To do this procedure you need to have one working key and one key that needs to be programmed.

1) Get in and close all doors.

2) Turn on the ignition and turn off quickly. (No more than 5 seconds) to start the process. Next action must take place within 30 seconds.

3) Remove the 1st key.

4) Hold the key up near your left shoulder (this is so it is closer to the remote receiver antenna.

5) Hold down the unlock button and press the lock button 3 times. Release the unlock button and the doors lock which confirms the operation.

6) Quickly repeat steps 4 & 5 for key #2 etc.

If it does not work, try doing the keys in opposite order. Key 2 then key 1, vs 1 then 2.



Method 3:

Alternate if you do not have a working remote

1. Turn key to position 1 five times very quickly 2. Remove key 3. Hold unlock button then press lock button 3 times, release unlock button.

4. If you have another key do the same button pressing within 30 seconds 5. Turn on ignition to finalise.

PLEASE NOTE: This programming procedure programs the remote control part of the key. Any transponder chip for the immobiliser (starting of car) will not be programmed and must be done by a specialist.

 

[poortomsacold]

The receiver is inside the clowns nose on the bottom of the mirror, since you have no lights on the mirror just check if its getting power to it, absence of power may be the cause. If you lock the vehicle using the key in the door the alarm is not set, it will only set if the locking button on the key is used. Handy to know that if you suffer from false alarm activations albeit the car won't be protected but the doors will be locked.
The following methods can be used to sync keys when you have a working receiver
BMW Z4 - Key Remote Programming

Three methods to try:

Method 1:

1. Working from within the vehicle and with the doors shut

2. Turn ignition to position 1 and back to off within 5 seconds.

3. Remove the key from ignition and press and hold the unlock button for 15 seconds during this time press the key lock button 3 times within 5 seconds.

4. Release both buttons.

5. Doors will lock and unlock to show correct programming has occurred.



Method 2:

To do this procedure you need to have one working key and one key that needs to be programmed.

1) Get in and close all doors.

2) Turn on the ignition and turn off quickly. (No more than 5 seconds) to start the process. Next action must take place within 30 seconds.

3) Remove the 1st key.

4) Hold the key up near your left shoulder (this is so it is closer to the remote receiver antenna.

5) Hold down the unlock button and press the lock button 3 times. Release the unlock button and the doors lock which confirms the operation.

6) Quickly repeat steps 4 & 5 for key #2 etc.

If it does not work, try doing the keys in opposite order. Key 2 then key 1, vs 1 then 2.



Method 3:

Alternate if you do not have a working remote

1. Turn key to position 1 five times very quickly 2. Remove key 3. Hold unlock button then press lock button 3 times, release unlock button.

4. If you have another key do the same button pressing within 30 seconds 5. Turn on ignition to finalise.

PLEASE NOTE: This programming procedure programs the remote control part of the key. Any transponder chip for the immobiliser (starting of car) will not be programmed and must be done by a specialist.

That's really helpful, thanks so much.

Will try to dismantle the mirror itself to see what's going on in there. If all looks to be in order I'll get a replacement and try that. The new remote key I have from BMW is cut and starts the car so fingers crossed if I get the receiver working I'll be able to program it to the car.

Can I ask what lights should be showing/flashing on the clown nose even when locking the car with the key rather than the remote, i.e. does it still.flash or come on at all? Thanks.

 

[colb]

Locked using the button on the key the clowns nose will flash red indicating that the alarm is set.
Locked using the key in the door lock the clowns nose will not light up or flash as the alarm is not set using that method of locking.

 

[poortomsacold]

Locked using the button on the key the clowns nose will flash red indicating that the alarm is set.
Locked using the key in the door lock the clowns nose will not light up or flash as the alarm is not set using that method of locking.

Ah okay, thanks. Any other way of telling if I am getting power to the mirror?

 

[colb]

Test bulb or voltmeter on the wires inside, should be able to find the power wire and ground in there, might be fed from the roof courtesy light circuit but would need to find a wiring diagram to be certain. Should think you should find power in the mirror with the ignition on if indeed it is being fed.

 

[poortomsacold]

Test bulb or voltmeter on the wires inside, should be able to find the power wire and ground in there, might be fed from the roof courtesy light circuit but would need to find a wiring diagram to be certain. Should think you should find power in the mirror with the ignition on if indeed it is being fed.

Thanks - will try to test that later on. Having paid attention to the mirror today (I didn't even know about the auto dimming feature but have read the spec of mine and it apparently has it) and it appears to be permanently dim. Not sure if this is another sign perhaps that the whole mirror unit has failed? Or if power were to be restored it may lighten up and the receiver work?

 

[enuff_zed]

I had a pair of dimming mirrors. Off the car they seemed very dark. I think they need power to lighten not the other way round. That would gel with having no power to the mirror

 

[poortomsacold]

I had a pair of dimming mirrors. Off the car they seemed very dark. I think they need power to lighten not the other way round. That would gel with having no power to the mirror

That's helpful to know, thanks. Will try to see if any power is getting to it and take it from there.

 

[poortomsacold]

The receiver is inside the clowns nose on the bottom of the mirror, since you have no lights on the mirror just check if its getting power to it, absence of power may be the cause. If you lock the vehicle using the key in the door the alarm is not set, it will only set if the locking button on the key is used. Handy to know that if you suffer from false alarm activations albeit the car won't be protected but the doors will be locked.
The following methods can be used to sync keys when you have a working receiver
BMW Z4 - Key Remote Programming

Three methods to try:

Method 1:

1. Working from within the vehicle and with the doors shut

2. Turn ignition to position 1 and back to off within 5 seconds.

3. Remove the key from ignition and press and hold the unlock button for 15 seconds during this time press the key lock button 3 times within 5 seconds.

4. Release both buttons.

5. Doors will lock and unlock to show correct programming has occurred.



Method 2:

To do this procedure you need to have one working key and one key that needs to be programmed.

1) Get in and close all doors.

2) Turn on the ignition and turn off quickly. (No more than 5 seconds) to start the process. Next action must take place within 30 seconds.

3) Remove the 1st key.

4) Hold the key up near your left shoulder (this is so it is closer to the remote receiver antenna.

5) Hold down the unlock button and press the lock button 3 times. Release the unlock button and the doors lock which confirms the operation.

6) Quickly repeat steps 4 & 5 for key #2 etc.

If it does not work, try doing the keys in opposite order. Key 2 then key 1, vs 1 then 2.



Method 3:

Alternate if you do not have a working remote

1. Turn key to position 1 five times very quickly 2. Remove key 3. Hold unlock button then press lock button 3 times, release unlock button.

4. If you have another key do the same button pressing within 30 seconds 5. Turn on ignition to finalise.

PLEASE NOTE: This programming procedure programs the remote control part of the key. Any transponder chip for the immobiliser (starting of car) will not be programmed and must be done by a specialist.

That's really helpful, thanks so much.

Will try to dismantle the mirror itself to see what's going on in there. If all looks to be in order I'll get a replacement and try that. The new remote key I have from BMW is cut and starts the car so fingers crossed if I get the receiver working I'll be able to program it to the car.

Can I ask what lights should be showing/flashing on the clown nose even when locking the car with the key rather than the remote, i.e. does it still.flash or come on at all? Thanks.

Well I’ve started the weekend with a success story! Took the mirror off and then apart. Cleaned all of the circuits and connectors with circuit cleaner, put it all back together and I noticed there was a very dim red light from the nose. Tried programming the key for 10 or 15 minutes, was about to give up when the car locked, unlocked and I now have a working remote key!

Only issue is the range - I have to hold the key above the mirror on the outside of the car, but wonder if this may be the battery as I think they charge from the ignition and this key has never been used in the car?

Anyway, it works. Still to test the dimming part of the mirror as it’s too dark to test it now.

Thanks so much colb for the programming guidance - much appreciated! And it’s pretty nice to have sorted something that BMW couldn’t…!

 

[enuff_zed]

Well done Tom!
If you have a rechargeable toothbrush then try leaving the key on the base to see if it will charge.
Then sit smugly in the sofa revelling in your success

 

[poortomsacold]

Well done Tom!
If you have a rechargeable toothbrush then try leaving the key on the base to see if it will charge.
Then sit smugly in the sofa revelling in your success

Thanks Martin! The great thing about this forum is the ability to learn something new every day.

But quite what my wife will make of it all I don't know - she wasn't overly impressed when she came back one day to find a rear wing on the dining room table, but to now find a BMW key on the toothbrush charger will be a life moment to treasure I'm sure!

 

[colb]

Could well be low battery in the fobs having to get close to the mirror to activate the lock/unlock. If the charge on the toothbrush charger dosn't improve things then maybe the battery inside needs changing, they don't last forever and our cars are getting old now. There is a seller on ebay that will refurbish keys which includes replacing the battery. Once refurbed you would have to sync the key(s) again.

 

[poortomsacold]

Could well be low battery in the fobs having to get close to the mirror to activate the lock/unlock. If the charge on the toothbrush charger dosn't improve things then maybe the battery inside needs changing, they don't last forever and our cars are getting old now. There is a seller on ebay that will refurbish keys which includes replacing the battery. Once refurbed you would have to sync the key(s) again.

Thanks Colb. It’s a brand new key from BMW so shouldn’t be the internal battery. Will report back once it’s had a chance to charge. I read elsewhere that somebody else had a similar problem and a replacement mirror fixed it for them, so I have a fallback position if the charge doesn’t sort it.

 

[colb]

As its a new key might just need use to charge it up to capacity, may have been on their shelf for some time, see how it performs after giving it a charge.

 

[poortomsacold]

It's currently on the toothbrush charger as I type this!

 

[poortomsacold]

Update on this thread. Key charging didn’t help as still had to hold it over the windscreen to get the car to lock and unlock.

So I picked up a second hand auto dimming replacement rear view mirror for £30 (that BMW wanted £440 for), fitted it in less than five minutes and I now have a properly working remote key which I’m very pleased with!