Failing at changing the W124 centre vent

One of the items on my todo list for the 300TE was to replace the W124 centre vent.   A couple of the slats were broken, so I could not direct the air, and the open/close control was not working either.   The open/close control is especially important in winter, as heat doesn’t come out of the centre.

I was told that the RHD part is different to the LHD part, so when I saw a reasonable deal on the RHD part, I purchased it.    The part number (at least for my car) for the W124 centre vent is A124 830 08 54.    From looking at the new part, it had screw holes on both sides, so I assumed that it would require the instrument cluster to be removed.   Turns out that the right screw hole is not used, so the vent can be removed without removing the instrument cluster.  On seeing that, I looked in the EPC, and actually I don’t think the RHD and LHD parts are different.  And I think that extra hole proves it.

There are four things holding the vent in.   A screw on the left hand side which is accessible with the glove box door open.    Then there is a small bolt holding the vent onto the flap behind it.   This is removed with an Allen key, 4mm if I recall.   It is accessed from the right hand side of the vent, near the centre (pictured above).   Finally there are two clips also on the right hand side of the vent.   One of mine was broken, but the other I could get up with a long thin screwdriver.    It helps to have the new part on hand to see where they are.

Finally, there is a small bulb that fits into a slot in the back at the bottom centre.   This was blown on my car.

I was able to get the old vent out pretty easily.   And generally putting the new vent in is the opposite of removal.   There were two slightly tricky aspects.  The first involved changing the bulb.  I bought a bag of these dash bulbs about 10 years ago when I had my black 560SEC.   I used the final one one for this repair.   Firstly, I couldn’t get the bulb to work at all.   Then I noticed that none of the dash lights were working.

I realized that the instrument cluster must be installed and plugged for the dash lights to work.   This also explained why the light for the outside temperature gauge wasn’t working.   I re-installed the instrument cluster, and then found that while the bulb wouldn’t work when fully inserted, being out about 1mm had it illuminated.

It took a few goes to get the bulb holder into its socket, and the wire fed into the wire holder at the bottom of the vent.   On the first few tries, the bulb pushed all the way in and stopped working.    Eventually I had it in and was greeted with a properly illuminated dash.

The next part was to push the vent in.    That was trivial.   Lining up the allen bolt with the plastic connection for the flap was harder, but I found it easiest with the flap and vent wheel in the closed position.

It was all going well, until I tightened that bolt too far and snapped something.   I’m pretty sure its the plastic piece that goes onto the flap.   This is really frustrating as fixing this was the primary reason I was installing the new vent.     I can’t see that plastic bit as a separate part, so I suspect I will need to get a flap from a wrecked car that has a good plastic part and transfer it.     I’m really annoyed with myself, I was being careless screwing in that bolt.

I still have a slight improvement, as the bulb works, and I can at least direct the air left and right.    But the main reason why I spent about $250 and an hour of my time is a big fail.