Hi, I have a 1998 e300d that I purchased recently and it is doing great with the exception that I cannot get heat out of the floor vents.

Even when I specify floor only on the temp controls, it just seems to ignore it, instead it always blows out of the defrost vents.

When I select the floor vents only, I do not hear any sounds of flaps moving etc.

We are currently experiencing sub-zero temperatures here, so any help would be greatly appreciated!

Thanks!

The 210 shares one aspect of the older systems - vacuum actuation of the various flaps in the climate control system. This is driven from a "harmonica" valve behind the glove box.

If you lose vacuum, you will default to fail safe mode - defrost flaps open.

The source of the vacuum is the vacuum pump in the engine. On the vacuum label under the hood, look for the line that says "other consumers". The only "other consumer' in the 210 is the climate control system. The door locks and rear headrest dump control are from the PSE pump in a 210.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

The vacuum lines to the "other consumers" come from a splitter, a manifold of sorts, that is connected to the large main vacuum line connected to the brake master cylinder. Check to make sure everything is connected.

Secondly, if you get down in the floor and look at the transmission tunnel, you'll see a small heat vent on each side. Remove the vent cover and look inside to verify that the actuator rods are still attached to the air control flaps.

When I bought my car, both of these had popped off for some reason and I was having the same problem as you are describing.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Thanks for the replies!

After opening the floor vents to look for possible disconnected cable, I noticed that the flap would pull open, but would start to shut again slowly when released. Come to find out that there is an actuator (vacuum as mentioned) that opens and shuts the flaps, that part is what seems to have failed. I have the flaps opened right now, but will have to replace the actuator once it gets a little warmer.

Thanks for the help!