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MB Vito W638 instrument panel...malfunctioning, of course

My 2001 W638 Vito has had issues with the instrument panel for as long as I have owned it. I know that this is a very common problem on this generation of Vitos, so rather than buying a scrap part (probably just as faulty) from eBay, I sent the whole panel away to ACtronics (an auto electrical specialist here in the UK) for a complete rebuild. When it came back, I refitted it to the van...and there was no difference. I rang ACtronics, they said return it, they checked it, and it came back with a clean bill of health. Still no change.

Here are its particular idiosyncrasies:

The needle gauges will frequently die while I am driving: the speedo and tacho freeze where they are, and the fuel and temp gauges fall to below zero. Generally, they'll stay there, and won't come back to life until the engine is stopped, left for a while, and then restarted. Of course, now they are sitting at 60mph and 2,500rpm or whatever, so will give utterly ridiculous readings. They will reset if the ignition is turned off and on several times: turn the ignition on, wait for the warning lights to illuminate, turn it off again, and the needles will drop roughly 20mph and 1,500 rpm respectively. Do this until they are at zero, and you are good to go. Until, of course, the whole thing expires again five minutes later. While the needle gauges are in this state of death, everything else - all warning lights and most of the illumination (more on that later) still function as normal.

So far, so typically Vito. But there are a couple of strange things that I have noticed:

After I park up (invariably with dead gauges) and turn the engine off, no amount of coaxing (via the turning-the-ignition-on-and-off trick) will tempt the clocks back to life, until I open the driver's door. I'm not imagining it; as I open the door, the fuel and temp gauges come back to life, jumping back up to zero. I assume that the contact switch for the interior light makes its connection, and somehow (bad earth?) this energises the instrument panel. It doesn't matter whether the interior courtesy light is switched to "off", and therefore not part of the circuit: the effect is the same. Also, you can switch the interior light on and off as much as you like without opening the door, with no effect. The door has to be opened.

And the other thing: the illumination for the fuel and temp gauges has never worked, not when I first bought the van, not after ACtronics' first rebuild, and not after their subsequent check, in which they specifically addressed this issue, amongst others.

I assume that there's some problem with the supply to the instrument panel, then. Is there anyone out there with any ideas or suggestions, or a similar experience? Does anyone have a wiring schematic for the loom that supplies the instrument panel? Why do all the warning lights always function as they should, but the needle gauges are intermittent? And why on earth should the fuel and temp gauge illumination not work in the van, yet tested ok at ACtronics?

Thanks in advance for any help, suggestions, sympathy, commiseration, practical advice, feedback, jokes, abuse, whatever..!
 

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Umm, drive along with the door open ;)

It does sound like you have a bad earth and the clocks are getting their feed from the door switch when it's opened. So you really need to find the earth wire for the clocks and look for breaks, etc. Or just run a replacement
 

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Umm, drive along with the door open...
:yelrotflmao:

Kez, that's probably the most practical advice I've had yet. These clocks have driven me crazy, and I'd try anything.

But yes, a bad earth is my first guess. Waaaay back in 1987 I had a Lancia Beta Coupé (actually less rusty than the Vito), and that had a few crazy electrical gremlins which I traced to a bad earth on a headlamp mounting.

Does anyone here have a wiring schematic for the loom that supplies the instruments? There are two multi-plugs, with about 20 contacts each. One or two of those contacts will be an earth, but I have no idea which...
 

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Discussion Starter #224
Try:

1, Remove the door switch, then drive around, see what happens

2, Remove door switch and short out the wire from the switch to the body so it continuously lights up courtesy light, then drive around and see happens

3, If above doesn't change the behaviour go to 4.

4, Check wiring in door boot, may be a possibility of wires shorting/and/or broken causing problem

5, Let us know how it goes :)


Cheers
Sarge
 

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Thanks, Sarge.

Wiring in door boot may well be an issue, as my central locking has the dreaded lock-unlock-lock sickness. I read somewhere that broken wires in the door boot are a prime culprit.

...but I'll go through your list in order.

I'll let you know how I get on.
 

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help, help ,help,i'm trying to get my vito w638 auto ready for its test and i'm having some dramas with (amongst other things) the lights,so here goes:
1.no parking lights front or rear with the exception of one number plate lamp.
2.no brake lights
lights that do work:
1.headlights hi /low beam & flash
2.reverse lights
odd stuff:
no lamp failure on instrument panel
brake interlock to auto gear selector works fine,goes click and releases from Park
relevant fuses under steering coloum appear to be ok
also,is there a relay in system ?

update:
power to fuses as it should be.
brake light switch working.

does anyone know the whereabouts of wiring diagram for a vito w638
any help or useful ideas are most welcome,thanks
 

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Hi,
Does anyone know how to connect a cooler fan type QBA 12V part nr.050 912 30 04 from W211, to an old W115 (300D)?
I mean, that cooler is fitted with an advanced state of the art brushless motor that comes with a 2+2 pins connector.
Thanks,
 

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Discussion Starter #229
help, help ,help,i'm trying to get my vito w638 auto ready for its test and i'm having some dramas with (amongst other things) the lights,so here goes:
1.no parking lights front or rear with the exception of one number plate lamp.
2.no brake lights
lights that do work:
1.headlights hi /low beam & flash
2.reverse lights
odd stuff:
no lamp failure on instrument panel
brake interlock to auto gear selector works fine,goes click and releases from Park
relevant fuses under steering coloum appear to be ok
also,is there a relay in system ?

update:
power to fuses as it should be.
brake light switch working.

does anyone know the whereabouts of wiring diagram for a vito w638
any help or useful ideas are most welcome,thanks


Check any and ALL earth points you can find, then see what happens. Remove them and sand down to clean connection, clean and refit.


Cheers
Sarge
 

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thank you

g´day again,
Many thanks to Sarge,the problen is now solved,it was stupidly simple.
Lamp control box(behind the instruments) had loosened itself from the multipin plug.all lighting issues seem to be resolved(for now),on to the next job,glow plugs or ABS?me thinks glow plugs.once again many thanks,Paul
 

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Hello everybody.

I have read all the posts and really looked hard, but it seems that the allocations of relays and fuses are still a well kept secret in the Vito 112 model.

Can anyone please help me out?

I have a fusebox and relays under my drivers seat, but I have no allocation chart for the fuses that makes any sense. In the instruction book the fuses are named as allocated according to a pattern like this: 1-1, 3-2 and so on, and also in positions and with numbers on.

However the actual fuses are on a board with three rows, numbered from 1 to 36, thus not adhering to the instruction manuals way of allocating them (Or any pattern found in this forum).

I am desperately looking to find the fuse and the relay for the electrical windows.

Can anyone help me out, either by displaying an actual map of fuse allocation and relay positions or tell me exactly which fuse and relay is for the electrical windows?

Thanks in advance. This is a great thread in a great forum.

Ted
 

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Hi Sarge can you help me, my 2005 cdi is showing the dreaded fuel rail pressure fault, have changed the fuel filter and did not help, wondering where to go from here
 

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Hi, can anyone help me with a wiring diagram for the central locking (lock at speed)relay system? It a 112cdi 2002 auto
I can hear a relay click in the left footwell when I get up to about 30km/h
And I want to disable it by either removing the speed signal going to the central locking or simply pulling this relay for the auto lock
I have an intermittent problem with the rear and side doors very quickly unlock then lock when I hit 30km/h
Please help!
 

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Discussion Starter #234
Hmm, I would check there isn't any air getting in the fuel circuit, is there any fuel leaks anywhere?

Have you had the vehicle scanned to see if there is any faults logged in the car's computer?


Cheers
Sarge


Hi Sarge can you help me, my 2005 cdi is showing the dreaded fuel rail pressure fault, have changed the fuel filter and did not help, wondering where to go from here
 

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Discussion Starter #235
Hi, can anyone help me with a wiring diagram for the central locking (lock at speed)relay system? It a 112cdi 2002 auto
I can hear a relay click in the left footwell when I get up to about 30km/h
And I want to disable it by either removing the speed signal going to the central locking or simply pulling this relay for the auto lock
I have an intermittent problem with the rear and side doors very quickly unlock then lock when I hit 30km/h
Please help!
I haven't worked on these in a while now, but have you done the basic clean up of the door contacts and checked the wiring isn't broken etc?



Cheers
Sarge
 

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Yes sliding door contacts are cleaned and good,
Replaced a couple of broken wires in the front doors for windows, mirrors, and locks and now it locks every time correctly (which it didnt do before)with the central locking key
But I still have the intermittent unlock/lock with the auto lock at speed.
The only way I can simulate the very quick unlock/lock is to open a sliding door and manually lock that door and then close the door, it then does the quick unlock/lock.
It's much quicker unlock/lock than trying to lock the car with one of the front doors or tailgate not closed fully
Hope it makes sence to you?
Any wiring help would be great
 

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Hi, can anyone help me with a wiring diagram for the central locking (lock at speed)relay system? It a 112cdi 2002 auto
I can hear a relay click in the left footwell when I get up to about 30km/h
And I want to disable it by either removing the speed signal going to the central locking or simply pulling this relay for the auto lock
I have an intermittent problem with the rear and side doors very quickly unlock then lock when I hit 30km/h
Please help!
Can anyone help with the schematic for the C/L system?
 

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Hmm, I would check there isn't any air getting in the fuel circuit, is there any fuel leaks anywhere?

Have you had the vehicle scanned to see if there is any faults logged in the car's computer?


Cheers
Sarge
Hi Sarge, just to say thanks as you are the only person who helped me out and answered to my cry for help!!

The fault was the main wiring loom had been rubbing against the eyelet on the top of the engine and had exposed wiring which was shorting to earth.

Thanks again mate.

Regards Gary
 

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Discussion Starter #240 (Edited)
Hi Sarge, just to say thanks as you are the only person who helped me out and answered to my cry for help!!

The fault was the main wiring loom had been rubbing against the eyelet on the top of the engine and had exposed wiring which was shorting to earth.

Thanks again mate.

Regards Gary
Your welcome Gary, sorry wasn't much/any help but really glad your sorted Pal. Thanks for posting the fix as I'm sure it'll help someone at some point :)


Cheers
Sarge
 
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