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How do you remove the BCM

#1
Hi I have just aquired a 55 plate Micra Sport +. The rear wiper is not working. The motor tests out OK so it has to be the wiring or BCM the problem is I can't figure out how to remove the BCM.
It is the black box at the front behind the radiator isn't it

Thanks in advance,

ColinJ
 
#4
Thanks Chaps, I'll try that

I downloaded a service manual and to check the wiring from the BCM to the motor you need access to terminals 71 and 23 of the BCM. Problem is I can't find the BCM (I think its the black box near the radiator). If it is how do you get access to these connections ?

ColinJ
 
#5
Better to avoid interfering with the BCM if possible, by more simply doing a hard reset of the BCM by disconnecting the car battery for 10 minutes & then re-entering the radio security pin code number.
BCM is under the headlamp assembly & is upside down, thus terminals v difficult to access.

Good luck
 
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#6
Gents,

The reset worked !! Many thanks.

Actually, removing the motor wasn't a complete waste of time as I found one of the mounting brackets hanging in space as the spot welds had failed. Two self tappers reattached it.

ColinJ
 
#7
Micronistas,

My rear wiper problem is back and another BCM reset was required. I recall my SEAT Toledo exhibiting a similar problem with its 'Convenience Unit' when the central locking would not extinguish the flashers thus draing the battery. It turned out to be a relay in the CU which I managed to replace. It wasn't easy as the relay was soldered to the circuit board. However I trained as an electronucs technician which helped.
This leads me to believe the same problem may exist with the Micra BCM. I think it unlikely that Nissan would use a transistor to switch a shunt wound DC wiper motor when a relay would do a better job of dealing with inrush currents.
My question is has anyone seen a photo of the internals of the BCM with the components identified ?

ColinJ
 

John_D

Club Member
Radio Code Guru
#8
Gents,

The reset worked !! Many thanks.

Actually, removing the motor wasn't a complete waste of time as I found one of the mounting brackets hanging in space as the spot welds had failed. Two self tappers reattached it.

ColinJ
Funny you should say that, I also had to re-attach on mounting bracket where the spot weld had failed.....
 
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