W202 Instrument Cluster Bulb indentification and unit Removal

[W202Chris]

Im in the boat, i have just got a C220 (W202) 1994 and have a bulb out and another intermittant. Again reading the Haynes Manual it recommends taking off the airbag and steering wheel. Other people say it can be pushed out from behind without removing the steering wheel, my steering wheel is non adjustable, so i get the feeling it has to come off? There is a video available on You Tube showing the removal using the hooks but its not complete so its hard to understand completely the process. If anyone here really has all the answers please let me know. Also to throw further light on the subject i have a freindly ex Mercedes Mechanic I know that i use for work i dont have the time to tackle my self and he is telling me it takes 1.5 hrs to get the instrument cluster out and same to put back in, he says there are hidden clips to remove. I dont know if im being given a bum steer so he can earn a bit more out of me or not. If its a quick job then i will do it myself, but im worried about the risk of accidentally setting off the airbag as replacement airbags are expensive. Any comments are welcome.

 

[Dec]

The cluster can be removed by pulling out with 2 pulling hooks, either Mercedes hooks, about £15, of homemade hooks. It can also be pushed out from the back but can be very difficult to exert the force required.

The cluster can be removed without removing the steering wheel.

The key should be in the ignition to allow the steering wheel to be turned slightly to aid removal. When the cluster is out, there are 2 plugs on the rear of the cluster to be disconnected, the ignition MUST BE OFF while these 2 plugs are unplugged.

See also … http://forums.mercedesclub.org.uk/showthread.php?t=56734
PLUs... http://202tech.mkosonen.com/howto/instrument.html
Dec

 

[W202Chris]

Brill Photos thanks alot Dec, its all becoming much clearer now. If anyone does this it would be cool if someone could take a video showing the experience. If i decide to tackle it i will try to do some video

 

[Dec]

You should DI Y, allow yourself an hour, I have had it out before so it’s only 10 or 15 minutes for me. It is however possible, like me, to make complete balls of it and break the glass, when pulling, don’t twist the hooks or the will slip out of there notches and catch the edge of the glass tearing a chunk out of it.

Mercedes cluster hooks… http://www.funnyyouasked.com/Mercedes/W126/ExpValve/removal_and_replacement_of_expan.htm

Dec

 

[chris.k2010]

I may have missed it if someone has suggested it already .. i so forgive me.

There is one other way of taken the cluster out. I have taken mine out twice now changed the bulb that lights up the temp indicator and after doing that putting the whole thing back ... the clock one decided to go awell ... typical !

Anyway .... above the swtich that you turn the hedlights ect .. on there is the speaker grill for the tweeterthis pops out relitively easier with a flat screwdriver ( i just used the one in the boot tool kit )

-you will then see two screws for the air vent to hold it in place, undo them and put them in safe place.

- next stage is to get that air vent out, now dont worry not as bad as it sounds...... with flat screwdriver you'll need to lever the air vent up a bit because there are two clips molded in the air vent to hold it in place ...... and with some jimmy'ing the thing will pull out.

- you can then once you have this out put your fingers in space where you removed the vent and to the left you'll be able to push the instrument cluster from the right hand. will take some effort

- this will pop the right side of the cluster out.

- then then shimmy your fingers around the outside of the cluster to get some grip on the left. Then work that side free.

thats one of the ways i got mine out

the other was mentioned on here already i took the cover off under the steering wheel layed on back legs in the air and pushed it from behind. But the second time went trough the air vent which i found easier.

I have a w202 1998 C240 no adjustable steering wheel but did get it out so can be done !!!

the hardest part was puting the plugs back on the back of the cluster (fiddly) especially with sausage fingers like mine.

Good Luck

 

[television]

Welcome Chris and thank you

 

[KOMPRESSIT]

Malcolm your excellent advice helped me last year to sort out my ABS on my car (W202 1996 C230K) - you quite rightly diagnosed the solder joints on the controller PCB, which I soldered up and have been fine ever since.

I now have a new issue and wondered if you (or anyone else) can help solve it. It happened suddenly when I went to drive my car a few days ago - There is no life in the instrument cluster except left / right blue indicator lights, airbag light and the battery light which all operate as normal. The speedo, rev counter, temp guage, clock, mileometer, ABS lights & all other warning lights are all 'dead'. The car still drives Ok and the ABS works Ok.

To me this indicates fuse / power / earth issue. The only problem is where to start looking. I had thought of taking out the instrument cluster to have a look for any loose wires etc (have read the posts here for the method).

I then thought it might be worth asking as there is probably a clue in that everything is dead apart from the 4 lights - turn indicators, airbag light and battery indicator light (which work as normal).

Thanks in advance for any advice.

 

[KOMPRESSIT]

Re my posting above - I've just removed the instrument cluster and can't see anything wrong there - plugs are secure enough at the back etc.

I started checking voltages in the engine compartment and there's a small black plastic box (approx 2" * 1") with a lid & three power leads attached (at the passenger side of the engine compartment next to the diagnostic socket). The lid unclips and I'm sure in the past that at least one of those leads was +12v. When I measure now there's none of them at +12v.

I'm hoping a broken wire somewhere rather than anything more major, hopefully not a computer fault!

 

[Dec]

Is the box in picture below the one you are referring to?

With the ignition ON, and after 30 seconds;

-Will the Red “handbrake ON” warning light come on if the parking brake is engaged?
-Will the Blue headlamp warning light come on when the stalk is in the flasher or high beam position? (Outside lights need to be ON)
-When the outside lights are ON is there any illumination at all on the instrument cluster? AND do the window switches illuminate around the gear stick?
-Are your brake lights working or rear number plate lights as there is mention of instrument cluster and instrument cluster illumination on my fuse cards below…fuses 3 and 15.

If the fault cant be located elsewhere then there may be a fault on the clusters PCB board in the form of a failed component or connection, not an easy thing to diagnose.


Dec

 

[KOMPRESSIT]

Hi Dec thanks for your reply.

I've checked the fuses - they are all fine (& fuse10 =14v with engine running & hazzards are OK), exterior lights all work, no illumination lights at all on the cluster with external lights on, red handbrake light doesn't come on, blue main beam light doesn't come on, the rear license plate lights are OK.

Absolutely nothing in the cluster works apart from the 4 lights I mentioned above (left & right turn indicator, airbag which goes out, battery which goes out when car running).

Since my last post:
-I disconnected the battery for 15 mins - no improvement.
-I removed the 2 connectors from the cluster, then re-seated - no improvement.
-I did notice two loose wires (orange + orange/brown) near the rear of the cluster outwith the harness of wires connected running to teh cluster - look like they have been 'pulled' out of somewhere but don't know where they come from.
-I also noticed the lights around the heater controls don't come on either (were OK a few days ago). The lights @ the electric window switches don't come on either.

I am beginning to think these loose wires have got something to do with it, or the pins at the rear of the cluster socket (where they attach to the pcb) need re-soldered?

I have read various internet posts etc about clusters failing, but I haven't come across one like mine with almost total fail except 4 lights.
Any further possible causes / checks /suggestions are most welcome.

Thanks.

 

[Dec]

Are you saying that even the speedometer, rev counter, fuel and temperature needles aren’t working either?

Dome, window switches, ash tray, heater control and cluster illumination are all on the one circuit the dimmer control is what controls these lights, if that were faulty it would explain the above consumers not working.

However the dimmer would have nothing to do with the warning lights faults, these warning lights come on for 30 seconds when you turn on the ignition or until you start the car, its just to confirm that all these warning bulbs are in working order.

In the picture below, there is a “gold” relay just under the left socket, my guess is that has some thing to do with the 30 second warning light check at start up.

The orange + orange/brown wires might have something to do with the outside temperature gauge, is there one fitted to your car. Put up a picture if you can of the wires in relation to the cluster plug.


In the absence of any other ideas you would probably have to go in deeper and inspect the PCB… http://forums.mercedesclub.org.uk/showthread.php?p=270927#post270927


Dec

 

[KOMPRESSIT]

Thanks Dec, you are correct none of the needles/gauges are working. The cluster is totally dead apart from the 4 lights I mentioned previously. Not even a flicker from the rev counter, speedo, temp gauge, no clock, no mileometer, no door buzzer. I've been examining the Haynes wiring diagram and apart from going cross-eyed, I am totally confused.

I just cannot see how 4 lights can work - indicator, charge light & Airbag without anything else working, the power for these go in through the same connector as to other items and they are not adjacent on the socket. So power is getting to the PCB.

I think the next step will somehow check that power to a non-opoerating lamp (eg handbrake switch) is getting to the cluster. If it is then the cluster PCB must be the cause of the fault, and I'll just hope that it is something obvious on the PCB.

Thanks again Dec any suggestions are welcome.

 

[Dec]

I just cannot see how 4 lights can work - indicator, charge light & Airbag without anything else working, the power for these go in through the same connector as to other items and they are not adjacent on the socket. So power is getting to the PCB.

-Haynes wiring diagram shows that charge light (c= alternator warning light) doesn’t go through a fuse but comes straight from the ignition switch when ignition is ON.

-Hazard warning lights work even if the car is locked so that fuse is live all the time, the indicators are related to the hazards.

-The air bag doesn’t seem to have a fuse, fuse 20 indicates Airbag fault indicator lamp.

That might explain why these lights are working.


Is there any power getting to fuse 3, the stop lamps and cluster are on that fuse so if the stop lamps aren’t working then there is no power going to that fuse holder.


It would be worth opening up the fuse box to see the connections to all the fuse holders, disconnecting the battery first.

There is 24 pins on one of the cluster sockets and about 21 on the other, halve of these are earths so there 22 wires going into the cluster, the cant be all bad…unless there is some component on the cluster that is knocking them all out…maybe it is something outside the cluster like the fuse box.

At bottom of picture, there is a 7th screw to remove, the fuse board should then manoeuvre...unclip... out with a bit of wiggling to get at the underside of the fuse box.



Dec

 

[KOMPRESSIT]

Hi Dec, thank you very much for your suggestions and excellent pictures.

The stop lamps are working OK, power on fuse 3 is Ok, I had already opened the fuse box and checked the fuses, but will now check the connections under the fuse box. I am now beginning to think solder joint / or a component on the cluster PCB.

I will try the connections under the fuse box first as you suggest, as it sounds like a possibility.

I now remember that I had driven over a bumpy road (+4 "traffic calmers") just prior to this fault appearing, so possibly a wire/ connector under the fuse box has moved out of position slightly).

I will post back when I have investigated further.

Thanks again.

 

[KOMPRESSIT]

Hi Dec,

I tried removing the fuse box, but couldn't access the nut to the left of the blue relay - it is partially obscured by the fuse box itself. So I decided to check the handbrake light-on feed at the console. It runs from Fuse 10 I believe and is a red/white wire, it was reading +12v at the i/p to the console and I know that is one of the lights not working.

(This suggests the feed from the fusebox is Ok and the problem lies within the console? -please advise if you think I have got this wrong).

Based on that I removed the console and now have it on the kitchen table. I have seperated the rear, but a bit worried about what to do next. I think I'll have to read your earlier posts to remove the gauges then have a look at the PCB to see if there's anything obvious wrong.

Thanks.

 

[KOMPRESSIT]

Hi Dec,

I have removed the PCB with guages still attached - I'm not sure how to remove them, there's no screws, just metal 'tangs' that have to be rotated, but then I still can't get them off the pcb. I looked at your previous post on another thread and the console I have is different - it looks like the gauges are linked and it looks like they all the guages come off together.

Am I right in saying a replacement console from a breakers wouldn't work in my car ?
If so, it looks like the only option may be to have mine repaired somehow.

Once again any help would be appreciated.

Thanks,
Kompressit.

 

[Dec]

On mine fuse 10 is instrument cluster, hazard warning flasher, I should think yours is the same?
You have it out now so you may as well investigate the PCB.

1… In order to access the back of the cluster, the torx screws, located at green arrows in picture, must be removed first.
2… Remove the 2 screws holding the temperature gauge from rear of cluster, pull out to unplug it.
3… If you don’t have an outside temperature gauge fitted, there will be a blanking cover fitted instead, removed the 2 screws holding it and remove.
4… Remove the 3 screws in each of the 3 dials, pull straight up to unplug each dial.
5… Remove 2 screws at large green arrows.
6… Don’t dismantle either the dimmer or clock adjuster knob.
7… Don’t pull or exert any force on either the clock or mileage counter.
8… The PCB board will now lift out of the casing.
9… There is 1 spring attached to the back of the dimmer knob, if you find a loose spring when you finish, then that is where it belongs, this is the only spring inside the cluster.

With care, the PCB board, in its dismantled state, could be tested live in the car, provided the 3 dials and temperature gauge are plugged back in and secured with there screws. Great care should be taken not to damage the dial needles and other components.

IGNITION MUST BE OFF WHILE THE TWO PLUGS TO THE REAR OF THE CLUSTER ARE DISCONECTED FROM THERE SOCKETS, OTHERWISE THE SRS (Airbag) WARNING LIGHT WILL STAY ON, REQUIRING DEALER RESET.


Dec

 

[Dec]

Is yours diffrent from the above?

Dec
Edit; you may not need to remove the 3 dials, the object is to see the back of the PCB.

 

[KOMPRESSIT]

Hi Dec,

Yes it is different - there's no torx screws (but metal clips) and the three gauges are linked by a clear plastic surround. (I would take a picture, but my daughter is away for the weekend with my camera). I can't see anything obvious on the rear of the PCB, but will use a magnifying glass to check for cracked solder joints though.

I double-checked and agree with your comment about fuse10 , but that still confirms the connection through the fuse to the console is in tact? (the output plugs @ the fusebox are connected). Perhaps I should check a few more feeds after examining the PCB just to make sure.

Any idea how the bolt in the fusebox (to the left of the blue relay) comes out - it is partially obscured by the fusebox itself, but the bolt got in there, so should be able to come out.

Thanks,
Kompressit

 

[Dec]

and a couple of nuts by the Blue relay 1. to remove to get at the underside of the fuse box.


Dec

Sorry, just had a look at those 2 nuts, the above statement is wrong, the 2 nuts don’t need to be removed, just the 7th screw, the fuse board should then manoeuvre...unclip... out with a bit of wiggling.

I don’t know if a console from breakers would work, the mileage would be wrong and it might have to be coded to the car.

If you can’t find any fault on the PCB it would be best to have the car put on STAR diagnostics…there could be a very simple remedy for the fault.

Dec