Steps to removing the dash in a W124. This is a 1990 300TE 4MATIC. See Jobs 46-8240, 54-6015, 91-660, 68-100, 68-105, and 68-150. See 83-568 and 83-665 for R&I of vacuum elements.

I attempted this repair because I first lost footwell heat due to a defroster pod leak and then found that the other two dual red pods (fresh air/recirc) also leaked.

1. Disconnect negative from battery.

2. Disconnect the Red SRS system plug beneath the passenger footwheel. This is extremely important or severe injury could result if the airbag is deployed when removing it.

1. On each rear (dash) side of the steering wheel there are two Torx screws (T27 size) to loosen. They are captive.

2. Remove the airbag and lock away from kids or curious adults. The red connector pulls from the rear airbag connector

3. To remove the steering wheel the Allen hex screw is removed. Once it is out you will see slight centering markings on the shaft (since 01/90) and the wheel, this aids in reinstallation.

This is the rear side of the airbag. Note the 2 pin connector in the centre.

This is the rear side of the 4MATIC steering wheel. There are 4 brass rings and one outer plastic ring where the 72 steering angle magnets used for 4MATIC are installed.

Here’s the view of the brushes. There are 6 electrical carbon brushes and one bigger plastic (whitish) springy brush (arrow) for 4matic angle sensor is at the lower right.

To remove the turn signal tree the three phillips screws shown must be removed.

Below is the speaker reveal moulding which came out before the grille.

4. Two screws hold the grille in, one in front and one in back on the groove.

5. The 10mm nut (arrow) in front of the speakers must be removed. These are the only top fasteners. The others are in front and on the left side. The speaker does not have to come out.

6. I missed few a shots, but next removed the gauge console cluster and then the side pillar panels. Then the side and centre airvents, the left and right lower dash panels.

7. Then the main dash lifts up and back. It will be tightly attached to the heater box with rectangular rubber gaskets.

The speedo cable (Arrow)

This is the dash out view. There is a large tube running across for structural safety or torsion.

Below is the little suction blower for the ACC temp sensor in the sunroof switch panel. It is also in the above photo on the right.

It ‘s easy to remove when the glovebox and lower right dash panel is removed.

Below is a view of the heater box, the two red dual diaphragm pods are for fresh air and the recirculated air flaps. Usually one of the diaphragms in each fails first. I changed both pods.

Each red pod is locked in with a black plastic tab that must be pressed in prior to rotating the pod to release the fingers.

The top black pod is the air diverter flap/centre nozzle air vent. This is supposed to representative as of 08/91, but my 04/90 car has it this way.

Once the cover is off there is another pod inside the box called the blend flap/centre nozzle but it is hard to see and replace.

The manual says to remove the heat exchanger first, but I have heard it will come out without removing the heater core.

I didn’t change either one, but should have.

Below is the white footwell flap pod, it can be replaced without removing the dash, only the control switch panel( 83-635) needs removing with two wood panel screws just above the radio and two on the module itself. The top dash is held down with two other screws and nuts not seen (top two arrows), these two hold the centre console to the upper dash.

The two notches for the screws ( top arrows) are at the top edge of the console. The top dash has two clips holding the bolts. Don’t drop the nuts or they will fall in behind the radio.

Another view of the heater box with the top cover and centre vent out. The air mixing pod is inside the box somewhere.

This view shows the right recirculation pod (partially hidden) and the on right the defroster nozzle flaps pod. It’s also a dual diaphragm pod and usually leaks like the other two.

I found that to test them properly you must pull the two vacuum lines off the manifold as the one diaphram fault is hidden otherwise.

Below is the vacuum manifold. The green line goes out to the intake manifold. The front 7 lines run to the 6 diaphragms and their 9 ports. There are a couple of tees so vacuum is shared on three pod ports.

You must pull off one line for single pods or two lines on the red duals to test the pods.

Below are a few pictures of the recirc pods first assembled then disassembled. I think they are similar with only the bar length and shape being different.

Long throw cap off. (Below)

Long throw diaphragm and spring removed.

The tear is noticed in the left black diaphragm below. This is the short throw diaphragm. The long throw diaphragm (right black) shows slight wear but no holes.

I believe the short throw diaphragm fails because of the long throw movement which folds the diaphragm over itself and because is no axial guide on the bar end so the plunger can move sideways due to the long metal bar.

Fully disassembled.