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2000 E320 4Matic Wagon
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15 Posts
Discussion Starter #1
My power door lock are not working now that temperatures have dropped into the 5 - 15F range.

In summer, there's no problems. As we get close to freezing temps outside, the locks get sluggish and I have to press the remote button 3-5 times to make them all lock. The last to lock is always the hatch lock. Sometimes, you can see the lock pins move ever so slightly every time you press the button, and then they eventually come down one by one with repeated presses of the lock button on the key.

Typically, after driving for a while (20+ minutes) the locks work fine - as if they warmed up, or something.

But now, when it's really cold outside, they won't budge AT ALL! - Even after driving the car until it is warm. I can lock the doors manually, but not the hatch, so I have to park it outside with the hatch unlocked. The cylinder was never used in the hatch and seems frozen (but not because of ice). Even in the summer, I can get the key into it, but not turn it. Guess this is a common problem.

What can I do to make my power locks to work again?

And is there a way to lock the hatch from the inside?

Thanks, hope someone can help me, I can't be the first to have experienced this.
 

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1999 E300 TD
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2,045 Posts
The good news is that the central locking system is not dependant on the weather. Cold or hot it just keeps pnumatically along.

For this potential solution you wll need a partner who will stay in the back seat area (back seat removed) while you are outside the car executing the central locking via the remote.

My questions are: While pressing the remote does the person hear the pump motor(under right seat) of the PSE working? When you execute the interior central locking button what happens??

Regarding locking the hatch from the inside--see owners manual for details.

Stay warm!!!
 

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2000-E320, 2012 Buick Enclave, 2004 Ford Ranger, 1973 Rolls-Royce Silver Shadow
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194 Posts
I've had a similar problem with our recent cold here in Florida. My door locks work fine, but my trunk doesn't want to unlock. I have to wait a minute or two and then it pops open!
 

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1999 E300 TD
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2,045 Posts
The remote trunk release like the doors and gas flap all have pneumatic actuators that open and close, however the electrical routing of the way they are opened and closed is different based on the remote or interior switch.

With the door issue, I believe(intuitive) the culprit is the PSE pump as logically all four door lock actuators couldn't go bad at once.

With you trunk, it could be a leaking vacuum line from the PSE to the trunk actuator or it could be a bad trunk lock pneumatic actuator. You would have to test the system to be more accurate.

One thing you could do is----do you experience the same delay in trunk opening when you open the trunk with the interior switch??

The good news for us, anyways, is that it is going to get warmer by Friday!!!
 

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2000 E320 4Matic Wagon
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15 Posts
Discussion Starter #5
Thanks for the replies. I still need to try and have my wife stay in the car and listen to the pump.

However, I doubt it is a vacuum leak. Remember, the locks work fine when the temp gets above freezing. Also, I hear no hissing or anything like that.

The interior lock button doesn't work at all - same result as when pressing the remote.

From reading other posts I seem to understand the pump runs until a certain level of vacuum/pressure is built up, and then stops. Could moisture (i.e. ice) in the system block one or more hoses and trigger the shut-off? Seems like it would have to be a central hose that was blocked, because if just one hose to a door was blocked, the other doors would work fine...

Finally, the mechanical lock switch on the inside of the hatch cannot be slid to the locked position. it used to work, even if it was tough to slide over. Wondering if ice in/around the mechanism could be blocking it...? However, it's not like I just took it through a car wash or anything.

Would it work to try and disconnect the vacuum hoses from the pump and try and activate the locks with compressed air or a vacuum pump that my neighbor has?

Thanks again for your suggestions, I'll keep you updated on what I find.
 

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1999 E300 TD
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2,045 Posts
FYI my observations on the remote trunk release was for the gent who indicated his doors worked fine however was having a long delay with the trunk opening.

So your interior trunk release and central locking don't work or they also produce a delay??

If you choose to pressure test the system, remember the max pressure(converted from mbars) is 8.7 psi with a small permissible leak after one minute----do not go higher or you will damage the door, trunk and tank flap actuators. Good luck
 

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2000 E320 4Matic Wagon
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15 Posts
Discussion Starter #7
It was the hatch lock...but now what?

Went out yesterday and tried to get the lock cylinder to turn in the hatch. It is 'frozen' from years of not being used prior to me buying the car. Heated it for a few minutes with a hair dryer and also put some lubricant in it. Suddenly, the locks worked again with the remote, though slowly. After a bit more heating of the lock area in general, the locks all went back to working normally.

The lock cylinder still doesn't turn, though, so whatever was frozen in the lock mechanism was elsewhere.

I wonder what can have frozen up in there, and what I can do to prevent it...? Should I take off the inside panel and coat everything in some form of lubricant or sealer? Don't want to risk putting something on the plastic/vacuum parts that'll damage them. Any suggestions?
 
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