One for the W124 gurus.

[tron]

My 11996 E300D has the air vent control block beside the airbag as expected but it only has four electrical connections instead of the normal eight.
I would like to understand what is going on within it as I am fairly sure that there is a solenoid that is not being controlled which works the central vent. Under the bonnet, somebody has added a solenoid valve with a Y connector on it and I have found that blocking the open end pulls the flap in so I am guessing somebody has done a repair. There ought to be a signal I can find that works this solenoid which I cannot yet find. I would far rather find out how it is supposed to be and either evolve a better repair or fix what is actually broken as it is a valve issue and not a pod issue.

Does anybody here know what I am talking about? It would be great to find a valid diagram.
The VIN if it helps is WDB1241912F34xxxx.
Thanks for any help received.

 

[brigadier]

For wiring diagrams try here - Anyone hosting Supplement 14? - Mercedes-Benz Forum

 

[optimusprime]

Google - Mercedes 124 Naintenance Mnual Index .

 

[tron]

Thanks guys. No sign of the correct data in any of those, I'm afraid.
All this data is too early for my car, alas, which is why I'm having trouble getting hold of it.

 

[optimusprime]

Tron did you look .. i found it in the manual before i sent it to you .Shows the location of the box .Must say it should be Mercedes 124 Maintenance Manual Index . But if you looked thats it .

 

[tron]

I have looked through section 83 but haven't fiound it. Please let me know the reference, Optimus as If it is correct I need it and if not, I will at least be able to exclude it.
Thanks, Tom.

 

[bolide]

AFAIK there are no complete or useful diagrams easily available to the public. An MB dealer might have the info on EPC & WIS. You can get access to EPC & WIS online if you have a PC

Nick Froome

 

[optimusprime]

Tron another one that might help , Mercedes -Benz Model 124 Service Manual Library I can see the boxes but no wiring diagrams i will look more.

 

[grober]

You might have some luck with W202 or even W210 diagrams Mercedes sometimes import certain units from their newer models to the last [ run-out] versions of older models for assembly line supply logistic reasons.

 

[optimusprime]

Tron same manual i sent to you under page 24 Electrical Trouble Shooting ETM Thats the only one i can find .You can make it larger if hard to view it .

 

[grober]

Under TEMPMATIC CLIMATE CONTROL post 1987 =3 diagram - Air control section it details two separate switchover valve units - an upper Y26 [ block of 5] and a lower Y25 [ block of 4] which presumably is the one you can see. As you probably already understand each solenoid controls engine / vacuum pump--- vacuum from reaching the vacuum actuator diaphram units in the air con unit. So we have a possible 3 problem options
1 the aircon control unit is faulty
2.the solenoid valve in question is faulty
3. the vacuum actuator is faulty
to explain the jury rig.
Fortunately it would appear the actuator is OK from your descripition leaving the other two possibilities- you need to trace back that jury rig solenoid wiring back to its source to part find the answer.