1996 s 320 - PeachParts Mercedes-Benz Forum

gfdent · #1 08-13-2002, 10:19 PM

I have a problem with my trunk handle. It won't retract into the trunk, and the trunk light switch on the dash console stays lit. Does anyone know what the problem is ('96 S320)?

Gilly · #2 08-13-2002, 10:23 PM

There is a microswitch built into the lower part of the latch which may have failed. it signals the system that the trunk is closed so the handle will retract and the light in the console will go out. I believe it may also be keeping the trunk light on as well. I alxo believe the whole lower latch will need replacing, I don't think it's available seperately.

Gilly

turnne1 · #3 08-14-2002, 10:24 AM

sounds like a vacuum pump issue...I think the pump that controlds the trunk is in the trunk...a few years ago I had the same problem....mine would actually cycle after is was fully closed and try to open again....setting off the alarm!!!...the doors always worked fine though...but the fix was a new pump

Warren
1992 300SD 145K
Columbus Ohio

gfdent · #4 08-15-2002, 06:44 PM

I believe it to be the pump also, because the trunk will latch at the lower unit but the pump? you dont here, and it will not pull the trunk close all the way. also, I put WD-40 on the trunk handle and it is operable manually, I can push it in and it slides back out.

where is the pump located?

turnne1 · #5 08-16-2002, 08:04 AM

I think the pump is in the trunk on the left under the carpet....have you tried pulling out the #9 fuse for 30 secs and then putting it back in?...some people have had luck resetting the pump that way....but I hear this is only a temporary fix...because it will occur again at some time

Warren
1992 300SD 145K
Columbus Ohio

Gilly · #6 08-16-2002, 09:41 PM

You're not getting it. I am not saying the trunk lower latch isn't latching, I am saying the microswitch is bad because when the trunk lower latch closes, it trips the microswitch which should operate the pump. I also believe this is why the light on the console switch is staying lit with the trunk closed, this all fits together, as the closed signal would be from this switch.
The pump for the handle is NOT the one in the trunk, nor will removing fuse 9 affect this part of it, the pump in the trunk and the "fuse 9 trick" is for when the trunk lid or door closing assist is inop, not the outside handle.
The outside handle retract operates from the PSE pump, which is under the rear seat on the right side.

Gilly

gfdent · #7 08-16-2002, 10:04 PM

Ok Gilly, I see what your saying. and you might be right, because I just checked the lights in the trunk on each corner and they are both burnt out, and your right the fuse #9 trick did'nt work.

Maybe I have two problems, this microchip does make since the way you expained it (the light remains on in the dash) and tells the system that its closed. but, also, the close assist wont close the trunk either (it wont work).

where is the microswitch located exactly and will this have an effect on the pump closure at all or are these two seperate problems.

my trunk is getting annoying because it looks like its not shut.

geof D

Gilly · #8 08-16-2002, 10:16 PM

Geof:
I didn't realize the trunk closing assist (pull down) was inop, I am relatively certain that this may also be caused by this switch, I was kind of wondering if that worked or not.
The switch is located, if you are standing by the trunk with the lid open, look at the lower latch, then lean in and look at the rear wall of the trunk (like looking at your knees if the car wasn't in the way) and there actually is an opening there for a little trigger device that allows you to shut off the trunk lights. This little trigger is actually acting on the switch (microswitch, not microchip). I can't remember if you can buy just the switch or not.
You may want to check out the owners manual, i think there is a way to make that upper catch retract so that it doesn't have the gap around the lid, so it looks normal. In any case it may be better to have the problem diagnosed professionally rather than guessing at what may be wrong.

Gilly

gfdent · #9 08-17-2002, 12:00 AM

Gilly, Gilly, Gilly, you are absolutely correct. it is associated with the microswitch. I found the switch as you noted and depressed the switch with my finger, WALA, the pump activated, the trunk closure retracted, the trunk handle retracted and the red led light on dash turned off...... But,..... there must be something missing .... because when I close the trunk I can't see anything that will activate this switch. something should activate this switch when the trunk is closed but nothing happens. Do you have any thoughts on this?

ps.
there is a spring in this housing where this microswitch is located, but does not seem to be attached to anything and I cant see where it should be attatched too either........

Pumps are good,
microswitch is good.

geof D

Gilly · #10 08-17-2002, 06:15 AM

Geof:
If you are mechanically inclined you can possibly do a repair on it, been awhile since I've messed with one. i'm pretty sure, going by memory, there is something on the latch that breaks and prevents the switch from working and you end up with replacing that lower latch assm. Best bet if you want to fix it is to start by taking the black plastic panel off on the trunk opening sill.

Gilly

gfdent · #11 08-17-2002, 12:38 PM

thanks

Ill start on this today and let you know the results!

gfdent · #12 12-24-2003, 01:14 PM

Finally had time to fix problem. And Gilly your right! there is a little circular plastic piece that triggers the microswitch which breaks, and you can't just replace this part. but must replace the lower assembly, cost about $87.00. Measured latch holes where bolts go in, to make sure I have the same measurements on the new latch. easy to install and trunk latch works perfect now. Also, I can now replace the light bulbs in the trunk, because these would burn out because microswitch would think the trunk was always open.

Thanks for your help.