Re: 240D lights problem

Roland Franzius wrote:
RF schrieb:
Thanks Tiger.

Tiger wrote:
You probably just have to replace the ignition switch.

I'll try to eliminate everthing down to the ignition sw. and then will order if necessary.

There is always power to the light switch... that's why you can turn on parking light when engine is off.

Ouch! You're right. I should have noticed. It's looped from the ignition sw. - does not go through it.

Are you sure there are no bunch of brown wires on metal chassis inside the cluster area? Most MB I worked on has some kind of bunch of groundings behind the instrument cluster.

I had a close look at the diagram for the cluster of instruments and there is indeed a ground shown. However, I haven't found it yet.

Some years back I silenced the seat belt buzzer because it was loud and would always run for about 20 secs, which really annoyed me. There was no sensor in the belt latch. I have a built-in reminder to fasten my seat belts :-) and it never fails. I did find a loose brown wire with a 1/4" wide spade connector but I don't see any matching spade connector.

There are a few interesting things behind the cluster, including that collection of grounds you mentioned that are hitched to the chassis. I missed it because the felt pad was pushed up too far and held up by the speedometer cable.

I found a black plastic box about 2.5"x1.5"x3/4" dangling from 5 wires that are wrapped with tape. Four wires are connected to the box via large blobs of solder and the 5th wire is free but it has a blob of solder on the end and I can't see where it might have broken off from any of the solder blobs. There is one free terminal on the box that has a smooth cover of solder but no evidence that the 5th wire broke off from there. Is it possible that that box is the seat belt buzzer?


Check your radio connections and/or a 12V plug for external gadgets (telephone, icebox?). While MB radio is off with ignition key position 0 many people want radio or cooling even with ignition key off and make an extra soldering connection to 15 - battery direct somewhere. So the internal 15-connection will be cold a soldering or has fallen off from the connector.

I have no external gadgets nor other external connections.

The instrument cluster has 4 round sockets - a little over 1/4" diameter - and two are the connectors for the glow plug and the seat belt light, which is always dark. There are two free sockets but I have no idea what they were for - probably some items that I did not specify when I ordered the car.

I haven't yet followed the wires that are connected to the ground behind the cluster.
Tomorrow morning I'll have another look, before my garage turns into its usual
furnace state these days.

Have a great weekend :-) and thanks again for your advice.


Its time now to circulate the model and year of your 240D ;-)

Opps! I missed that one. It is a 240D model - 1983 year.

I have removed the instrument cluster and it's now connected via the clock
connector only. Surprisingly the metal casing is grounded and the clock is
still running.

.

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