This all came about because of this
- Difficulty Level:
Door Light Loss Of Power (Engine & Gearbox - )
I can not be held responsible for any problems anyone encounters whilst attempting this task. This is the way I which I completed the replacement and it' may not be the text book solution.
So after having the donor MICU for a few weeks I decided it was time to change it.
There's very little tools needed to complete this task
10mm socket, extension bar, ratchet.
Set of precision screwdrivers
Bradawl (this will come apparent as we go along).
Mini fuse puller.
So safety first
Undo the negative connector to the battery terminal(10mm spanner).Pretty obvious why you are working with electrics.
Once you have done this you have to gain access to the MICU which is situated on the outer bulkhead of the drivers footwell.
This panel is held in place by 2 standard clips at the front end and by two hooks behind the door seal and finally two slots under the carpet trim
Place a small screwdriver under the carpet trim just enough to get you fingers under and carefully lift the trim(it is only clipped down).
Unclip the trim to about the area of the boot catch. From this picture you can see one of the holes on the main trim that attach to the carpet trim to hold it in place.
Once you have done this you have to hold the side trim near the front and just gently pull it,which loosens the 2 clips, then you have to jiggle it about a little to unhook it from the door seal and the carpet trim. Once out put to one side as now the fun begins.
I am right handed and the MICU is on the right side so it was going to be a lot of left hand or lie on my back in the footwell and use my right hand both means were used.
This is what you can expect to see once the trim is removed.
There are 8 plugs on the front face. 2 green ones on the right side as you look at it
I removed the 8 on the front first. The white ones have a snap clip that you lift up and it releases the plug from the socket.
The green ones and the small yellow one have a push in clip once in you can pull the plug off.
The large yellow one took a bit of thinking out because it looks like 2 plugs built into one after something resembling the krypton factor I worked out that the outer is spring loaded and that you pull the outer out to release the whole thing.
Finally release the plug on top of the MICU press clip and pull out
The next thing is to remove the securing bolts there are 2 of these one at the bottom and the 2nd at about 1 o'clock as you look at it.(didn't get a photo of it but will highlight where they are later.
Once the bolts are undone you can gently pull the MICU away from the bulkhead to allow you to remove the 2 green plugs from the side. You can now start to remove the plugs from the rear.
You are limited for space because of the large plug in the centre top only having a short length of harness without cutting the clip and releasing more.
This was the awkward bit as I had to try and do them either left handed or lying on my back in the footwell trying to use my right hand and because the clip releases are so small and you can't turn the thing round you have to do it all by feel.
I got to the stage where my finger ends were that numb I couldn't feel anything and I still had 4 plugs to release, this is where I sent out an SOS and @Nighthawk came to the rescue advising the use of a long screwdriver feeding it down the back onto the release clips to push them in and prise out the plug.
Having tried a precision screwdriver with little joy I turned to this
With great success I finally got the remaining plugs out so it looked like this. Rear wires and plugs the good thing about these are they are all different plugs so you can't get them mixed up when you put them back.
So finally removed I now have 2 x MICU
The left is the replacement.
Looking at the bottom you can see the part where one of the 10mm securing bolts fit and in the top right is the second one. You can also see the trim clip on the left side(blue) that has to be removed and fitted in the recess in the trim before refitting.
The refitting is basically the reverse of what you have just done some points to note.
Check all fuses and relays before fitting.
Rear plugs start with the lower green ones, then the upper ones leaving the short main one till last. Just align the plug push it in firmly till you hear a click you then know it's firmly in place.
After fitting the side plugs realign the MICU to the bulkhead and replace the securing bolts. The upper one you will see there is a relay in the way so you need to gently bend the bracket out of the way so you can get in with the 10mm socket.
Replace the front connectors
And it should end up like this
Replace the trim
Place the trim clip into the recess on the trim and put the rear end under the side carpet trim make sure the 2 hooks go under the door seal once hat is done push firmly on the front and you will hear the clips click into place. Then make sure he door seal is seated correctly and then realign the carpet trim and push down till you hear the click again.
You are then in a position to test everything.
Finally I removed the ignition key closed the door so nothing was taking power, then reconnect the Negative terminal to the battery. I then closed the bonnet and then the moment of truth I locked the car using the key and to my joyous applaus it locked and after a short while I opened it.
Now to see if the initial problems had been resolved and if there were any other issues.
I opened the drivers door and the interior light and door light came on (result).
I turned on my headlights and the chime started ringing.
I checked every other thing I could think of from air con to washers to lights to horn everything worked so my work was successful.
I hope people can use this guide I'm always around for questions.
The down side was the time obviously this is something you can't rush invade you damage any wiring so all in all it took me just short of 5.1/2hours to complete.