W124 wiring diagram ?

[Mercedes 190E]

Hi Guys

Does anyone know where I can get a decent wiring diagram for my 1990 300TE ? I have the Haynes, but it seems pretty useless.
Thanks.

 

[Bolide]

I have the Haynes, but it seems pretty useless

You're absolutely right!

I've never found a complete set of accurate wiring diagrams. Which is a shame as it'd be very useful

Is there something in particular you're looking for? Most of the (relatively few) electrical faults are well-documented

Nick Froome
www.w124.co.uk

 

[Dec]

Dont know how reliable this is, but for what its worth... http://http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1990/300TE/SYSTEM%20WIRING%20DIAGRAMS/

Dec

Edit; That link was working 5 minutes ago, now its not, its up and down like a yoyo.

 

[Mercedes 190E]

Thanks guys. Nick-my problem is in another thread, but basically my rear courtesy lights dont work at all. When I checked, there were no bulbs in-the reason being that there is 12V to all the lights regardless of which position the dash master switch is in. I obviously suspect that the switch is U/S but just wanted to check the circuit to see if there is any other explanation.
Dec-thanks for that. Its down at the moment, but I will keep trying!

 

[The Crooner]

http://http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1990/300TE/SYSTEM%20WIRING%20DIAGRAMS/

Strip out the two http:// at the start of the address.

Worked for me.

Tony

Thanks for the link

 

[television]

Yes the switch is built into the lock, both with normal and soft closing I can send details of removing it

 

[Dec]

http://http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1990/300TE/SYSTEM%20WIRING%20DIAGRAMS/

Strip out the two http:// at the start of the address.

Worked for me.

Tony

Thanks for the link

Thanks Tony, don't know how I did that.

Dec

 

[Mercedes 190E]

Thanks all. Found those diagrams which will be very helpful in the future, but unfortunately I cant find lighting circuits at all !

Malcom-its not the tailgate switch I suspect, but the dashboard isolator as the 12V is present whichever position it is in.

 

[Bolide]

From your description I don't quite understand whether, with bulbs in, the lights are on all the time or off all the time

Quite a few circuits on a W124 have permanent 12v and the switch supplies an earth. I'd start with the rear door switches and see if they're giving an earth. With the dash switch in the "door switched" position these switches should make the four rear interior lights come on

The switch on the tailgate will be part of the door closer mechanism

I had one car where the interior lights wouldn't go off. After looking at circuit diagrams, swopping the N10 relay and the interior light unit I found a bent door switch... so look at the simple things first!

Nick Froome
www.w124.co.uk

 

[Mercedes 190E]

Thanks Nick. Yes, the lights are on all the time regardless of the dash switch position. Do I not understand the dash switch then? I though it had three positions-on, on if switched and off. I am getting power through to the lights on all three positions which seems odd.
I will check out the switches, basically by disconnecting them completely if nothing is obvious. How can I access the tailgate switch to unplug/check it?

Thanks for all the help so far-I really appreciate it!

 

[Bolide]

Thanks Nick. Yes, the lights are on all the time regardless of the dash switch position. Do I not understand the dash switch then? I though it had three positions-on, on if switched and off. I am getting power through to the lights on all three positions which seems odd.

Not really - as I say, a few circuits are like that. Those circuits have a switched earth. AFAIK the interior lighting circuit is of this type. You understand the switch correctly

The window winder motor feeds are similar - the feed to to the door is permanently live and the switch puts an earth to the motor

I will check out the switches, basically by disconnecting them completely if nothing is obvious. How can I access the tailgate switch to unplug/check it?

You have to strip the lower par of the tailgate to get at the wiring. It's then all on plugs & sockets

There is a connector block in the corner of the headlining immediately behind the tailgate opening. The various circuits are not labelled so it won't do you much good unless you can find out the wire colours

Logically, if the interior lights are permanently on then a switch (one of the rear doors or tailgate) is permanently closed. If you disconnect both rear door switches and the lights still stay on I'd suspect the tailgate lock switch

Nick Froome
www.w124.co.uk

 

[Mercedes 190E]

Thanks Nick. I will investigate.....

 

[Mercedes 190E]

Set about testing these lights today. Disconnecting the rear door switches has no effect at all, so it is probably the tailgate switch. Can anyone talk me through how to access it ? I have taken the board off, but cant see where it is!!
Many thanks.

 

[Bolide]

AFAIK it's part of the motorised lock assembly. Unplug it and see if the problem goes away

If it does, remove the lock and find where the switch is

Nick Froome
www.w124.co.uk

 

[Mercedes 190E]

Thanks Nick. Sorry to be a bit thick, but where is the plug to disconnect it? I couldnt see anything obvious....

 

[The Crooner]

John

I've just posted about this without searching - doh!

Did you resolve this?

Tony

 

[television]

Would you like the rear lock removal and check details, the switches are built into the lock on the electric closing version

 

[The Crooner]

Malcom

I've pmed you my email address.

Yes please

Tony

 

[television]

Malcom

I've pmed you my email address.

Yes please

Tony

Its sent, I hope its the right one

 

[Mercedes 190E]

I suspect that the courtesy microswitch is knackered in mine, but simply have not had time to test it. Easy enough though-a block connector behind the tailgate board disconnects the lock completely and if the lights then go out, I know what the fault is!! I have aquired a spare lock/switches, so when I DO get time to test, I should be able to sort it quickly. I'm just hoping it isnt the wiring loom at fault!!