Grr I am so cold W115 problem - PeachParts Mercedes-Benz Forum

Rudolphrocks · #1 01-28-2007, 03:15 PM

My 240D is so confusing! I have not the foggiest idea how to turn on the heat I have four sliders and one fan speed knob. I got the heat to turn off in the summer but I don't know how to turn it on now. TIA

Joe Bauers · #2 01-28-2007, 04:38 PM

From my recollection, pull the red knobs away from the center, fully. This should open the heat valves to let in the hot water. Turn the fan speed to the desired speed. Can't remember about the blue tabs--one is to put it on defrost, I think; the other to let in fresh air to run over the heater core, I think. Been a while since I had a 115. Good luck.

Joe B.

Irecando · #3 01-28-2007, 05:43 PM

How did you find a 240D of that year with only 19k?

Do you have any photos?

Eric
74 240D

Rudolphrocks · #4 01-28-2007, 09:07 PM

A girl i met in school was selling it, her grandfather owned it and it sat in his barn. Perfect Interior & light rust. No my pics got wiped in the big crash of 07, (see signature, that was the last time i used XP)

ABBWR · #5 01-28-2007, 10:22 PM

You should have four slides (two blue and two red). The top left blue lever directs air to the windshield. The lever toward the side of the car is open and toward the center of the car is closed. The top right blue lever directs air to the drive and rear floor area. Again, center - closed, side - open. The two red levers control heat on the left side (left) and right side (right). Levers to the sides - warm, and to the center - cold. the blue levers control the volume of air and both should be open for heating.

You also have a three speed blower switch. Obviously, turn it clockwise to adjust the blower.

Remember that if you have fresh air vents above the sliding levers, opening that simply allows fresh air to come in from outside.

Lastly, make sure that your air conditioner is completely turned off and you are not using that as another blower control.

Hope that helps.

Bill

meltedpanda · #6 01-29-2007, 10:36 AM

Bill is right , make sure the right blower is working, and that your switchover valve is functioning. On mine I really need to engage it full counterclockwise to get the heater fan to come on,

Lycoming-8 · #7 01-30-2007, 03:27 AM

"Make sure the right blower is working, and that your switchover valve is functioning. On mine I really need to engage it full counterclockwise to get the heater fan to come on."

Did all of the W115's have this feature? Ie, where there are two fans and the correct one is selected by vacuum? Although not currently in service, I have wondered about the old '68 220D/8 and if it had this setup. Never had to tear too far into the center console, just for radio maint. So have never seen the real innards.

meltedpanda · #8 01-30-2007, 08:28 AM

if it is outfitted with factory air then I believe all the w115 had this set up, at least the ones I have seen, I am sure someone will know for sure. The blasted heater fan location I believe is the same in all the w114/115

ctaylor738 · #9 01-30-2007, 08:47 AM

I think all 114/115 cars with factory air had the two blowers and the vacuum acivated change-over controlled by the AC knob. The vacuum also positions the flaps for AC. The compressor does not come on until you engage the fan.

The mechanism can be seen on the left side of the console by the dash.

Mark DiSilvestro · #10 01-30-2007, 10:23 AM

Quote:

Originally Posted by ctaylor738

I think all 114/115 cars with factory air had the two blowers and the vacuum acivated change-over controlled by the AC knob. The vacuum also positions the flaps for AC. The compressor does not come on until you engage the fan.

The mechanism can be seen on the left side of the console by the dash.

This would apply to a '75 240D.

As for the '68 220D, If it has factory AC, my factory Service Manual for Series 114-115, dated May 1970, does show a first-version heat/AC control with a rotary AC temp control and a separate console-mounted manually-operated, horizontal lever, above the radio, to change from the AC mode & fan to heater mode & fan. I remember seeing that setup on a '69 230 and a '70 250, so it appears the vacuum-operated fan change-over started with the '71 models.

Happy Motoring, Mark

230/8 · #11 01-30-2007, 07:06 PM

The operation of the heater/defroster temperature and air controls is as described. Really pretty simple. There is no reason for no heat unless your under-hood valve is plugged or the control cables are not attached. Pray that your heater blower does not crap out. FYI, the center fresh air vent tends to short circuit all the heat ducts and sends outside air directly into the car, is it closed or open? Right is closed, left is open.

The AC and heat systems all used two blowers with the heater blower and AC blower both controlled by the same switch. The first version cars used a manual slide lever in the console to operate the AC flaps. Slide right to engage the heat ducts, slide left to engage the AC side. When slid to AC the manual slide also has a switch attached, riveted to the lever mechanism, that shunts the wiring so the fan switch will control the AC fan. Flip the slide back right and the fan switch operates the heater fan which is buried deep in the console behind everything MB could possibly cram inside the console area.

Helpful hint...if your heat fan dies, you should be able to use the AC fan to move air over the heater. Simply remove the AC belt so the compressor does not run (leave the wiring in place to maintain circuits) and select the heat temperature you need. You cannot use the AC to de-humidify winter air, but you can get hot air to move, it is just less efficient. I would not use the AC in really cold temps, you can freeze the evaporator solid.

Version 2 cars eliminated the manual slide for AC/heater crossover. Twist the AC knob CW to engage the AC system and you engage vacuum flap controls at the same time you change over the fan control and set the AC temperature.

All this is described in the factory CD ROM in job 83-500. If you do not have a copy I suggest you get one before they go out of stock. Seems that MBUSA is gradually reducing the various manuals etc they sell.

Am I the only one who thinks all their "heritage" advertising is a lot more slogan than substance?

230/8

Lycoming-8 · #12 01-30-2007, 09:59 PM

Thanks for all of the updates on the W115 HVAC systems. As I mentioned earlier, this car is currently not in service but would still like to re-activate it some day. Is nice to know how things really work or at least are supposed to work. Will file this all away for the future.