hmroz

Hello, I have a 2003 ML320, and yesterday I noticed I have only left low beam, and when I switch to high beam I only have right high beam! I can hear a clicking noise coming from behind the left headlight! Also when I pull back the headlight lever both high beams work that way. Was wondering if anyone one out there has encountered this issue! Any help would be super, thanks, and have a great day

gsfent

Are you sure both "high" beams work when you pull back on the lever? I thought when you pull back, you get low and high beams, as opposed to just low or high beams when you set the switch to low or high beams. if so, you are seeing the left low beam and right high beam.

I don't recall if we have separate bulbs for low and high beams on the ML's, but I believe we do. Check fuses. You can always swap bulbs side to side to confirm bad bulbs.

Regards,
Jerry

hmroz

Swapped bulbs, checked fuses, when you pull back the high beam lever, both high beams illuminate, and just the left low beam! I'm thinking I may need a combination switch???

Maj. Dundee

Originally you said you had one low beam on and then when you pull the stalk, you had one low beam and one high beam. Now that has changed to one low beam and now both high beams working.

The designation of left and right is determined as you sit in the vehicle, not looking at it from the front. So now with that information:

1. Which low beam does not operate?

2. Which headlight is the noise coming from?

hmroz

Left low beam only when you turn lights on! when you push stalk forward only right high high beam works, when you pull stalk back both high beams and left low beam illuminate!

The right low beam does not work
The left high beam does not work
Clicking comes from left headlight.

Maj. Dundee

Let's only work with the right low beam not working as this will be the easiest.

The way this confusing system works is when you turn the headlights on it sends a signal to the AAM which in turn sends a signal to the EAM and then to the headlights.

Remove the covers on the steering column and access the connector to the light switch. It should be an 8pin connector with:

#1 pin being Pink
#2 pin being Blue operates R/S low beam
#3 in being Orange operates L/S low beam

Turn the headlights on and with a test light or volt meter, check to see if there is battery voltage at pin #2 Blue wire R/S low beam

Also check pin #3 Orange wire L/S low beam. If pin #2 does not show voltage and pin #3 does, then you are assured that the problem is with the combination switch.

If you get voltage at both pins then your problem is either with the AAM or EAM. Post the results and we will go from there.

hmroz

Thanks! I will check it out this Saturday and let you know the outcome!

hmroz

Ok, so finally was able to test those wires, and they both power up fine! To be on the safe side, I borrowed a used operational combination switch from a friends salvage yard! Still, same problem. One low beam, one high beam! Now I have a bigger problem! I disconnected battery to change comb. switch and now my windows, moonroof, or mirrors won't work?..

Maj. Dundee

You didn't need to remove and replace the combo. switch to check it. The only thing you had to do was remove the elec. connector from the old one and plug it into the new one and check its functionality.

If you are still having the problem with the windows, roof and mirrors, remove and reinsert the K14 relay then check for operation. If not do the same with the K15 relay.

hmroz

Ok, so I removed and re-inserted both k14, and k15 relays under the hood. I'm at a total blank with this problem? Would a faulty BCM cause all off these problems? Again, thanks for all responses and help!

Maj. Dundee

When you changed the combination switch you should know that up to 2001 the switch had one part number and 2002 and beyond it had another. From what year was the replacement switch from?

Working with just the windows, turn the key to position #2 and in the right side fuse box, with a test light or DVOM check to see that you get voltage at both contacts of fuse 24 & 25 (green circle). If you do then there should be no reason why the windows don't work.

If not, with the key in pos #2, pull relay K8 and check for voltage at pins 2 & 3.

hmroz

Combination switch is from 2003 ML. I checked 24, and 25 fuse. Both fuses have power at both points on the fuse! Went to a local repair shop that has Benz scanner and he said the scanner cannot comunicate with the module that controls the windows. Does that make any sense?

Maj. Dundee

hmroz, correcting this problem can't be very important to you because you are taking a week to respond. Understand that there are many diagrams involved with solving your problems (now that you have added three more to the mix).

I have to re- read these every time you respond a week later. Can you please perform these tests a little quicker.

For the windows, since you say that you are getting power to fuses 24 and 25, the windows should work since there are no relays or modules that control them. The window switch group is its' own processing center, hence control module.

Please re-check fuses 24 & 25 in the right side kick panel, for voltage on both contacts of each fuse.

For the sliding roof, remove fuse #4 and then reinsert. Then push and hold the switch back to the open position for 5 secs.

Swap relay #14 with a similar relay in the underhood fuse box and see if the features work.

hmroz

I apologize for my delay in responding! This is my fathers vehicle which I am trying to correct for him. Problem with this is, he lives 20 miles from me and I rarely see him during the week. Weekends are the most convenient for me! I am thankful for all the assistance that you have given me to try to resolve this issue. Thanks again and apologize for any delays!