Vito 638 loss of electrics

[quattroguy]

Hi,
First post but I have had lots of help from the forum from other helpful threads.

My Vito 638 112 has had plenty of problems but usually rust or injectors.

Latest problem is that after a none start I have no windscreen washers, heater or speedometer and the abs ebv and traction control lights are on.

During the none start event I was getting nothing when the key was turned. I was poking around under the bonnet while my boy was working the starter on and off when suddenly the van started. Dash symbols have been on and no washers, heater or speedometer since.

I've been all round the dashboard, steering column and under the seat but not a single blown fuse or anything obvious I can see.

Hopefully someone has had this before and can shed some light on the problem.

Cheers

 

[quattroguy]

I had another poke around today. I really need this sorted for the winter as It'll be next to useless pretty soon with no heater or window washers. I noticed today that the headlight adjusters don't work and the beam pattern is all over the place as well as the other problems previously mentioned.

No fuses blown. Nothing looks wrong with the inside of the ecu using a magnifying glass. Found a rusty earth cable with 2 thin wires behind the drivers side headlamp, sorted that and moved it to fresh metal. No change after that.

The black plastic unit in the steering column with all the copper tracks inside, some fuses in the front and two relays on the bottom. This is the SAM unit? It has a small circuit board inside, I'm starting to think that is what has failed as the big copper tracks are all intact at relay and fuse connections.

 

[m80]

Your problems sound SAM related, if your lucky unplug and back again might restore connections, maybe.
Otherwise, replace with a good one and you may be ok again. For that you need remove it and take the MB part number to be sure the replacement is the same and interchangable.
I don't know the 638 to comment further

 

[quattroguy]

Different black box fitted under steering column and still no change.

Either the one I've bought has the same faults or something else is kaput.

 

[quattroguy]

I've looked everywhere I can get to. Replaced the unit under the steering wheel, new brake light switch and checked every fuse.
Anywhere else I should be looking for something that could cause so many electrical failures at once?
I had someone try and get some fault codes from it but no power at the diagnostic plug.