My nagging ML problems

[ML Dude]

I've hesitated to go to the dealer over the following issues simply because I thought they were too minor to fix on their own.

1) since day one, the instrument cluster illumination at full brightness still leaves the temp/radio/other center console switches dimly light.

2) Both the drivers(especially this one) and the passenger windows do not rollup normally. The electric motor is very slow in closing the window.

You guys experience anything like this, are they known problems?

[G-Benz]

I'm not aware of those being "mass" problems. My sunroof closed and opened slowly once, but that was remedied with some lube. Should be a normal warranty fix.

As far as illumination, the "bulb" illumination is independent of the digital displays, including the radio. Mine is the same way (even worse on the SL).

[RDJ]

1) since day one, the instrument cluster illumination at full brightness still leaves the temp/radio/other center console switches dimly light.

Do you have the Bose Radio. The brightness can be configured within the menu options. Never had any problems with brightness of the other things.

2) Both the drivers(especially this one) and the passenger windows do not rollup normally. The electric motor is very slow in closing the window.

Our 2001 ML430 also has very slow windows. I just thought it was the design. I'll have to check out another unit to see if there's a difference.

[ML Dude]

Yep, I do have the Bose. But it's fine, it's the switches around it that are visibily dimmer than the instrument cluster or the radio LCD.

As far as the windows, I drove a 2001 ML320 and it's windows were faster than mine!

Too bad MB didn't give us a "one touch" close for the windows and the power roof

[Kuan]

So you guys seen MY02 yet? I went and saw it yesterday.

Kuan

[Gilly]

The 2002 has express up and down, all 4 windows. They don't mention an express open or close for the sunroof. i also didn't see where they mention anything about the Skyroof in 2002 either.....
Gilly

Isn't the 2000 or 2001 the last model years for the skyroof? I think those curtain airbags were the reason why.

[ML Dude]

Ah, I forgot one that came up and bit me this weekend....

The ML apparently has this timer driven pump to continue to circulate the coolant after the engine is shutoff. Once before, the thing ran continuously and totally drained my battery. Normally it runs about ten minutes or so and stops(this should be temp driven) whether the car is hot or cold.

Well, went to pull out bike this weekend and the ML was dead. Try pushing a 500 pound vehicle in limited space, it was no fun.
As soon as I got the battery charger on, the pump began running again. It ran and ran without stopping until finally there was enough charge to get an "ignition on" condition. It then shutoff after about ten minutes. I've been lucky that this has happened at home both times, I may not be so lucky next time.

My question is, where is the problem? In the timer mechanism, the pump. Since this is an infrequent problem, the dealer going to have a hard time shooting a diagnostic. What should I ask them to replace?

[Gilly]

Ed:
With all due respect, I don't think you should be asking them to replace anything. I would relate what you noted in regards to the aux coolant pump running, but leave it at that. Complaint should be: Owner states battery went dead, upon installing battery charger, owner noted aux coolant pump running.
The pump may have been triggered on if the charger was installed with the key on, then key turned off, may have tripped it on. I don't believe the power supply for the aux pump is through a seperate timing device. it would come from probably the ME control unit, or possibly the AAM. I could look it up if you want to know for sure. The aux coolant pump does run on a time interval only, not temp influenced.
Gilly

[ML Dude]

Gilly,

Since we last touched on this subject, I've been to the dealer twice. I reported exactly as you suggested and they didn't find any error codes or evidence of failure(I think they started the car a million times).
Since I had to return I insisted on talking to a shop foreman and finding out what we might do, the guy was very pleasant and wanted to help but he naturally did not want to start replacing everything without some indication of what was wrong.
Finally, we agreed to replace a relay which sends power to the pump and see what happens.

Well, today it was dead again after I came back from vacation. As soon as I clipped the charger on, the pump started running again. I know it's not clear if the ignition on did that, but all I know is the car won't start and I'm worried my battery is fried now.

I'm going to take it in and ask for a complete charging system check and battery load test, but, I'd like your input on what you'd look into. It seems to be one of those really nasty intermittent electrical problems....

Rgds, Ed

[Gilly]

Ed:
A relay powering up that pump doesn't sound right. I will try to get a little time to research that circuit a little, because it does sound a little fishy. Either that, or here's something you could try. With the key off, disconnect the negative terminal of the battery for maybe a minute or 2, then reconnect it. Does the pump run? I think it runs for 5 minutes or so, then shuts off. if it runs for only that amount of time (roughly), then I'd say we're on the wrong track with the coolant pump.
You could try sitting in the car and pushing out on all the doors to make sure one of the doors doesn't have a touchy switch that is making an interior light come on, and also be sure to check the rear hatch for this, as we have had a few touchy microswitches in the trunk latch causing the rear light to come on. Make sure the rear light isn't in the manual mode, I would think you would notice that, though.
Also, I don't suppose there is a chance you are accidentally leaving the headlight switch in that left/right parking light position?
Other than that, the only thing to suggest is having them do a careful resting current draw test, and have them make sure the battery is good, a good battery test, including individual sg test of each cell, could be just the battery.
Maybe even do an overnight test of resting current draw with a good VOM with recording function like a Fluke 88 has, to check for intermittent current spikes.
Gilly

[ML Dude]

Hey Gilly,

Thanks for checking into this! It has actually taken some time for me to trace where the drain came from and the culprit is clearly the coolant pump running for hours. This has happened more than once where I go the garage(it's quiet) and the pump is humming hours after the car was shutoff and the engine is now cold.
The problem is that it only does it intermittently and causes me a drained battery when I don't drive the truck for several days on one of the run-on's. That's when the battery is dead!
It's been quick charged about three times now to get me going and I've charged it four or five times when it's happened at home all in a year and a half.

Help!

Rgds, Ed

[Gilly]

Ed:
Well then, the answer in the short term is obvious:
For now, I don't think any harm will be done by disconnecting the connector for the pump itself, I assume you know where it is, over on the engine side of the metal firewall along side the battery. Even if power is being supplied to the pump, if the wire is disconnected, the pump can't run, so no drain will occur. This will help definitely isolate the cause. But MB wants that pump to run for good reason, so I don't suggest this as a permanant cure obviously. I need to do some research for you on this, hopefully Friday I can do this.
Gilly

[Gilly]

Ed:
I did a quick research on this, it seems the "obvious" short term answer isn't quite right. The relay that I believe was replaced, K19, the "circulation pump relay" also powers a small fan underneath the fuse box called the "module box blower". It's really a cute little blower, I had to replace one once. So, by only disconnecting the coolant circulation pump, you are fixing temporarily "most" but not all of the draw, as the module box blower can still run, which it probably has been when the coolant pump was running.
My new temporary fix is to remove either fuse 41 or K19 relay, your choice, the fuse is probably easier to find. Nothing else is on fuse 41, just the coolant circulation pump and the module box blower.
As far as a permanant fix, the K19 relay is activated by the AAM, All Activity module. I am unsure of the inputs that cause these 2 devices to run, but am fairly certain that the AAM is the ultimate problem and needs to be replaced.
Gilly

[Gilly]

Ed:
Here is further research on the aux coolant pump. This is all from the 1998 ML intro manual:
"System Operation
Besides maintaining a consistent coolant flow at low road speeds, the auxiliary coolant pump circulates coolant during cold engine operation to circulate warm coolant to the heater core and continues to operate as long as the engine is running (or the key is in position 2). The pump continues to run after the engine is shut down to prevent hot spots and heat soak conditions.
When the coolant temperature is 110C(212F) or below, the auxiliary pump runs for 5 minutes after engine shutdown. If the coolant temperature is above 110C(212F), the auxiliary coolant pump runs for 10 minutes after engine shutdown."
The AAM recieves both temp input direct from the engine coolant temp sensor, and also receives an input from the CAN, although the exact use of the CAN info is not stated. I am sure the module box blower runs in conjunction with the aux coolant pump, but this is not stated in the intro manual.
I am still suspecting either the AAM itself, or possibly the fusebox panel, which the AAM plugs into on the underside, inside the module box.
Gilly