The temp sensor is up in the dome lamp assembly, but the sampler blower is actually located beneath the right side outer dash vent. You need to remove the glove box to get to it.

You can test it by holding a small (1 cm square or so) bit of paper up to the little grill. If it won't stay up, the blower is either off the hard plastic and rubber hose or the motor is bad.

To remove the glove box, open it, remove contents (mine is usually completely full!) and take the two screws out that hold the latch ring in. Remove the push rivets by prying up the center section and then the base (may be stuck pretty bad -- the plastic distorts with time. If so, get new ones). There are 8 in the 124 chassis, probably 8 or so in the W126.

Once the box is free, pull the lamp assembly down and push it back up through the mounting hole, then pull the top center of the box down to clear the molded hook there. The box will then pull out.

Sampler motor is clipped to the dash lower panel right under the vent.

When re-installing, put the hose on the motor before you put it back in the clip. Otherwise, the hose tends to come off if there is any tension on it.

If the sampler motor is working properly, you need to pull the pushbutton unit and spray contact cleaner on the temp wheel rheostat.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!