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W163 ML320 2002
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71 Posts
Discussion Starter · #1 ·
Hi.
I have bought a W163 (2002) recently.
The problem is that power windows do not work immediately when i start the engine. I need to wait for 5 minutes or more. Only then does it start working.
Previous owner says that it is how it worked since he bought it. (he owned it more than a year)
Any idea about what could be the reason?
Regards
 

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W163 ML320 2002
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71 Posts
Discussion Starter · #5 ·
Hi. Thanks for support.
i inspected area. No sign of corrosion. (At least to untrained eye )
Voltage at both fuses was 12.36V. But i tested them after the 5minute delay period. So that time the windows was working.
To verify that i am checking the right fuses i removed them one by one and then windows did not work at all.

I found a 2 pin green relay (A000 544 04 56) just near the those windows fuses. Searching its code suggested that its overvoltage protection relay. İt was making high frequece sound. Removing it also prevented power windows operation.
So is it possible that this relay is not working properly?
To test it may i short circuit this relay by joining its pins? Does it carry any risk ?
Regards.
 

· Registered
Dallas, Texas
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13,384 Posts
Oh Sorry. You are right. it is not OVP relay..
Not sure how i got that name.
The voltage shows 12.18 in both fuses, if i am testing it correctly :)
That is little low. What is voltage reading at battery?

Do you have a scanner that can access LCP (Lower Control Panel)?
 

· W163 and General M Gremlin
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16,887 Posts
Nicat,
===>>> Please update your user CP info....

click on your icon----> click on Account Settings---->
goto Account Details----> add vehicle details---->
ADD your make model YEAR ----> click save
 
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· Registered
W163 ML320 2002
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71 Posts
Discussion Starter · #10 ·
That is little low. What is voltage reading at battery?

Do you have a scanner that can access LCP (Lower Control Panel)?
Thanks for your patience and help.

At battery terminals:
Ignition Off: 12.45 V
Ignition ON: 12.06 V
Engine On: 14.25 V


At Fuse
Ignition Off: 12.30 V
Ignition On: 12.07 V
Engine On: 13.95 V

Turned engine off after running 10 minutes
At Fuse
Ignition off: 13.00 V

Voltage raise immediately when you start the engine. But still windows do not work unless 5 minutes pass.

I do not have scanner. I can get it scanned in services.
Recent scanning did not show any error other than engine codes and SRS code.
 

· Registered
2003 C320 coupe, 2000 ML320
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1,202 Posts
Those passenger side fuse boxes are prone to corrosion when the sunroof drain leaks down the back side of them.. You might need to "pull" the box out and examine the back side very closely.. I think you said you had relay chatter ?.. That could be a sign of low voltage "when under load"..

PS.. I would start with the B+ (12v) and ground main terminals..
(Take them apart and clean them up)
 

· Registered
W163 ML320 2002
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71 Posts
Discussion Starter · #13 · (Edited)
After thinking about it a bit,... It sounds like you've got a bad ground on that box (relays)..
Thanks for thinking even more about this :)
I will try to remove it for further inspection.

I found a strange thing there. It looks like a cheap chinese device. It is what makes high frequency noise all the time.
And it is somehow related to power windows fuses nearby. Because when removing those fuses it stops making noise.
Edit: I removed that device. And power windows were still working without it (of course when they were in their operation period).
Wire Cable Auto part Technology Electrical wiring
Auto part Fashion accessory Wire
 

· Registered
Dallas, Texas
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13,384 Posts
At battery terminals:
Ignition Off: 12.45 V
Ignition ON: 12.06 V
Engine On: 14.25 V


At Fuse
Ignition Off: 12.30 V
Ignition On: 12.07 V
Engine On: 13.95 V



I do not have scanner.
With engine running you have 0.30V drop between battery and fuses. Less then 0.10V is perfect.
Try to measure directly. One probe on battery positive other on fuse.

Most scanner operators are looking for faults only. That is like listening to stereo with only one speaker plugged in.
First part is Quick Test (Auto Scan) compared to installed equipment. If I don't see stationary heater in my ML scan it's OK. It does not have one.

Here is look at live data in LCP.
 

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· Registered
W163 ML320 2002
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71 Posts
Discussion Starter · #17 · (Edited)
With engine running you have 0.30V drop between battery and fuses. Less then 0.10V is perfect.
Try to measure directly. One probe on battery positive other on fuse.

Most scanner operators are looking for faults only. That is like listening to stereo with only one speaker plugged in.
First part is Quick Test (Auto Scan) compared to installed equipment. If I don't see stationary heater in my ML scan it's OK. It does not have one.

Here is look at live data in LCP.
Thanks for patience Sir. i highly appreciate it.

This time Engine Running
Both probes on Battery terminals : 11.98
One probe Battery+ another in Fuse: 11.98
Both probes on fuse : 11.92

Engine and Ignition turned Off
Battery voltage: 12.20

is it normal to have 11.98 when engine ON? Restarted it 2 times. Both results were same.
PS: Tried after 20 minutes later. Still 11.98V and no warning light in dash.
 

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W163 ML320 2002
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71 Posts
Discussion Starter · #19 ·
Auto part Tire Automotive exterior Bumper Metal
Auto part Bumper Shoe Metal


Hi. My cousin (who is not actually a mechanic) found that the blue cable at the alternator was broken. After joining it the voltage level raised back to 13.70.
What is that cable for? Likely it was disconnected for a long time. Does alternator provide any electricity without that cable connected ?
Because we never had noticed battery failure yet. And yesterday i was able to observe 14V at battery terminals with this cable disconnected.
We inspected fusebox area carefully. No visible corrosion (at least to our eyes)
Anyway, at least one issue seems to be solved. :)
Now trying to make more inspections :)
 

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Dallas, Texas
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13,384 Posts
Without that cable alternator will not charge right after start at idle. It may start charging if you rev it. It provides external excitation current from instrument cluster through battery warning light bulb.
 
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