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Michael Warfield
Michael Warfield, Factory Mercedes-Benz Technician
Category: Mercedes
Satisfied Customers: 3135
Experience:  Mercedes-Benz Master Certified technician
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Trunk cant be opened by swith on door panel..key fob..headlights

Resolved Question:

03 sl500...locks wont work with remote
lock/unlock control on dsah wont work
when i try to open roof, display says "close trunk separater" which is closed
trunk cant be opened by swith on door panel or key.....both batteries in car are great and both key fob batteries are new
the display went crazy a few times showing all ,minds of random lights and icons and headlights flashing from high to low beams at different times...very strange!
Submitted: 6 years ago.
Category: Mercedes
Expert:  Michael Warfield replied 6 years ago.
Your PSE pump has failed or has gotten water on it. Check the pump by partially removing the vario roof hydraulic pump in the trunk underneath the load floor. The pse is surrounded by foam. Take apart the electrical connector for the PSE and inspect for corrosion. I can almost guarantee you will find some. Either water leaked in through the main trunk surround seal or the 3rd brake lamp. Check for cracks around the 3rd brake lamp. This is a common area to get cracked and then water can enter and corrode the pse pump. Hopefully everything will start working after just cleaning the terminals and control units. Let me know if you will need any further assistance.
Customer: replied 5 years ago.
there was slight corrosion on one leg but i cleaned it up well and still have the same symptoms. locks still wont work and still says "close trunk separator" when its closed.
Expert:  Michael Warfield replied 5 years ago.
You will probably have to replace some of the terminals on the connector and maybe the pse pump if the terminal replacement doesn't solve the problem. The trunk partition switch is wired directly to the pse pump so obviously there is still a problem with the terminals or pump module.
Customer: replied 5 years ago.

sorry, i was looking at the roof motor not the pump underneath. it was very wet and quite corroded on the small connecter. the circuit board was also corroted in one area. i cleaned it up pretty good but to no avail. still have the same symptoms. is there a way to test the pump, could there be a blown fuse or fuses . thank you or your help!

Expert:  Michael Warfield replied 5 years ago.

You can't really test the pump with the connector that wet but the fuse for it is located in the rear fuse box behind the passenger seat in the storage compartment. You have to pop the floor off of the compartment to access the fuses. There should be a yellow 20 amp fuse #71. There should also be a fuse chart in your spare tire took kit that will have a nice diagram. You could try resetting the pump by disconnecting the battery for a minute and see if that brings back your central locking too. If you hear the pump running, you know the fuse is ok and there will be no need to check it.

Customer: replied 5 years ago.
thanks, XXXXX XXXXX check that out tomorrow. if all this fails and i need a pump, does the circuit board and all of the other "stuff" inside the black box that houses the pump come with a new one? is it likely that the circuit board blew?
Expert:  Michael Warfield replied 5 years ago.
Yes, all the stuff comes with the pump including the circuit board. Yes, the circuit board is most likely damaged from the corrosion and is not repairable.
Customer: replied 5 years ago.'re fast. my gut feel is that i need a new one. any suggestions on new or rebuilt or where to purchase? also, is there a way that you're rated for your performance, you've been very helpful and i appreciate it!
Expert:  Michael Warfield replied 5 years ago.
I don't really see any aftermarket or rebuilt central locking/PSE pumps for your SL. I would suggest getting it from the dealer since you really don't know what your getting. You could be getting a pump that was water damaged and then cleaned up to temporarily work. Positive feedback is all that is needed for me to get the proper credit. Bonuses are always welcomed too.
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