Caligirl

I have a ML 430.
My heater does not produce heat.
I have replaced radiator, thermostat and all the fuses listed for heater have been checked and look good.
What else could cause this.
I am disabled and live in the mountains, it is getting cold here and really need to get this figured out.
Please, any ideas

jim_johnstone

If the blower motor is running, then it's possible that the heater core is blocked. Radiator flush might work. Sorry if it's not much help, but all I can think of atm.

Caligirl

Blower works real good, system was drained when radiator was replaced., there was no crud.

jim_johnstone

I do not have the schematics for the ML, but I gues you need to start eliminating things one by one. First would be the heater matrix, and see if it is hot. If it is then it will probably be a stuck or broken vent that directs the hot air into the cabin.
Check this thread as it might be the same issue:
http://www.benzworld.org/forums/w163...-wont-get.html

Rainers

there is a heater control valve that needs replaced. I had it done last year on my EClass and now I strong heat where before it's was almost no heat. Ytbe valve is located in the cowl by your windshield

Maj. Dundee

There is no heater control valve on ML's

Caligirl

I was looking online and it states that my model has a Climate Control Vacuum Valve.
Could this be it? And is it hard to change?

Maj. Dundee

I don't know where you found that info., but there is no vacuum valve or anything operated by vacuum. It is strictly electrical.

Did you have heating last year?

Caligirl

I lived in the desert last year, have never had to use before.
Would changing the radiator and thermostat this summer have done something?
Could it be a relay? if so, which one?

Maj. Dundee

In all probably your Blend Door Actuator Motor (red arrow) has become faulty because it was dormant for two years.

The top half of the Inst. Panel must be removed to replace it.

Caligirl

is it hard to do?
I have rebuilt motors (OLD CHEVY) and always have worked on my own vehicles,
I changed the radiator, thermostat, oil and even plugs on this car myself, but nothing else.
I can't afford to pay the dealer, and the one nearest me sabotaged it (loosened power steering hose and poked hole ion radiator) when I took it there to program remote.

Maj. Dundee

Yes and no. Removing the screws (must be categorized as to location) can be done by yourself, but helper needed to remove and install Inst. Panel.

This procedure eliminates the breaking of the tabs on the passenger side air bag deployment door and also eliminates the removal of the air bag. Only the top half of the instrument panel needs to be removed.

Also before starting, make sure that you have your radio code.

1. Remove left and right "A" pillar trim panels.
2. Remove upper and lower covers on steering column (3 screws).
3. Remove Instrument Cluster.
4. Remove center section of instrument panel (with plastic pry tools).
5. Remove radio (with keys).
6. Remove glove box
7. Remove defroster vent strip (with plastic pry tools).
8. Remove items, 6-7-9 if so equipped (with plastic pry tools)
9. Remove side panels #128
10.Remove small defroster vents (RED arrow) on either side.
11.Remove 3 screws holding the AC/Heater Control, but do not detach cables. Pull controller aside to reveal 2 large screws (ORANGE) below & remove.

Start by removing those screws indicated in red.

Pull the ends and the top of the lower portion of the instrument panel slightly away to reveal the two green screws.
The two screws are upward inside that cavity. Feel around inside and locate them by hand or use a small mirror.

Then remove the two screws indicated in green.

Those screws indicated in purple might or might not be there, depending on model year.

Then gently pull away the top portion of the instrument panel, all the time making sure that every screw has been removed.

After installing the new Blend Door Motor and before replacing the Instrument Panel, reattach the A/C-Heater Controller, start the truck and check the workings of the Blend Door in every temperature stage.

On re-installation, it might be easier to fit the upper dash if the end and middle A/C vent were removed. If so, remove them by unlocking them from the back side.

Hopefully I have accounted for everything and good luck.

Caligirl

Where can I get the "keys" to remove radio?

Caligirl

I have found and ordered the tools I need. And the new part.
Thank you for the instructions and pics.

Maj. Dundee

You are welcome.

Caligirl

I have one question before I tear apart my dash.
Is the ML 430 and M 430 the same location and instructions?
Mine is actually the M 430, I was told that MB only changed the name, nothing else, is this true???

Maj. Dundee

One in the same.

Caligirl

Thank you so much, you are very helpful.

Caligirl

I sent you a message, if you don't get please let me know. I need your expertise.

Maj. Dundee

You must attach the white corrugated hose and the two wire elec. conn. at the upper left of the Center Section.

Caligirl

I did just what you said, and checked to make sure the blend door operated before putting everything back together, I have a problem.
The blend door only wants to turn counter clockwise. Will not turn the other way.
So to see if it constantly does that. I took the old one apart and fist noticed that the large gear was broken. Then plugged the old one in and turned on the key and it just kept turning, no matter if control was on heat or AC or off.
Any ideas??????

Caligirl

Hopefully you checked the operation of of the motor while it was fixed in place and not holding it in you hand.

If you did it correctly, you must temporarily attach the white corrugated hose and the two wire elec. connector at the upper left of the Center Section for things to work.

Maj. Dundee

Please UPDATE YOUR PROFILE in USER CP to include the year of your ML.

Caligirl

I fixed in place, hose was in place and I never disconnected two elec. wires.
It only wants to go counter clockwise. I shut it off fearing it was going to damage new motor.
I had no problems with anything, until dealer "worked on my car" That is when AC quit too.
If I manually move levers I have heat and AC. Could they have messed with a fuse? or a relay? I have checked them and all look good.

Maj. Dundee

Please update profile.