coldchill

I've been working on this quite a while today and can not get the trunk open. Battery is totally dead. I have tried putting power on terminal on top of left inner fender under hood. The lock button works on both remotes I have but will not unlock trunk. I've tied both the unlock button and trunk button. I have tried both keys and neither will move in trunk lock. They work fine in door and glove compartment. Is there another way to open trunk to replace battery ? Thanks, Michael

KJI3jflarryfe93

do you have folding rear seats?
do you have one of them open so you can sneak in from the cabin to unscrew the metal latch holding lock arm in place?

MB trunk locks does have a design flaw with cylinder lock getting seized by corrosion.
if you only use remote but never use the metal key to unlock/lock trunk one day you are screwed when you need to pop your trunk.

spray lots of penetrating oil in lock, let it sit for a few HRS, see what happens if you can turn key to unlock trunk?

you can go to your dealership and order protective plastic caps for trunk lock and for drivers door to protect them from corrosion and filth.
I have these caps on my locks and they have worked great protecting cylinder locks

coldchill

My car is a convertible with the rear seats fixed in place, no access to trunk. I have lubed the trunk lock with graphite and it seems fine. Key just won't turn. No corrosion at all. I think it may be electric related. Thanks, Michael

KJI3jflarryfe93

your cylinder lock is jammed coz metal key was never used to exercise cylinder lock.
your car is it a one owner car or multiple owner car?
previous owners probably only used the remote to pop the trunk, maybe they never used metal key.
if you can't get trunk to pop, you're in serious distress!

you might have to repeat this procedure several times, spray penetrating oil let it sit for a few hrs, use an adjustable wrench as leverage while you turning the key with very mild force.
be carefull NOT to break your metal key.
insert key and push the cylinder all the way into the barrel with your key and then try to turn key back n forth.

maybe you should call a locksmith asking for pro-advice, or they could come over to you and try to help you out?

lowphat

If your CLK is a W208, then open your hood and look in the area of the driver's side above the wheel (inside the engine compartment). You'll find a little plastic box with two heavy guage wires going into it. The box may have a large "X" molded into the plastic. Release the tiny clips holding the top of the box shut. Inside is a POSITIVE lead that you can use to jump the car (or at least energize your electrical system) so that you can open your trunk in the normal fashion. Remember, the box houses a POSITIVE terminal. You'll need to ground (NEGATIVE) whatever source you are using to energize the system elsewhere, just as if you were preparing to jump start off of positive and negative battery leads.

cindyclk

...and if you can't access the trunk....go through first aid kit....grab seat release cable...then crawl into trunk.

always leave one of the seats unlatched!