Pancho

Remote trunk lock not working on W208 (430CLK Cabriolet)

Can open trunk by inserting key in trunk lock,
but button on fob, and button on dash do not open trunk.

Some tech told me it is a vacuum switch.
Have a friend that had dealer fix his on a C class, $800.

Any repair help/tips would be appreciated.

Whodat

I had the same problem. I had my trunk lock replaced. That fixed it. Don't know where this vacum switch is but I'd be interested in knowing.

Hitman0187

i would also be interested in seeing that as well. does your conv. top still open and close normally ?
also check and see if your rear defroster still works if your in a cold climate.

i have a simular issue and have been way to lazy to investigate a truck lock change. my conv top functions normally but the car thinks its not fully closed so it beeps and the light flashes...

Pancho

No problem at all with ragtop.

Key remote operates door locks and alarm OK.

5 fuses in locking system.
Removed all, tested them for continuity--OK.
Re-installed all.

When I press trunk button on key remote, buzzing sound comes from trunk lock. Removed lock, pneumatic actuator extends when press either key remote, or console button Doesn't seem to be air problem.

Hit it with WD40, no help. Trunk still will not open with remote or console button.

If pneumatic, then what is purpose of two electric leads ?

See link:
http://www.panchogun.com/FVWebPhotos...Trunk-Lock.jpg

Hitman0187

i would imagine they indicate if the lock is opened or closed to the cpu. in my case when the top is down and the movement is complete everything works fine. when its up the truck doesnt open except with the key. so im guessing the wires "complete" the circuit allowing the correct operations without damaging anything.

Hitman0187

great pictures BTW - i think whodat is right. your lock must be shot out.

macclk

It is probably not a Vacuum Switch, but the Vacuum Pump, the "tech" mentions, and the position of that is in the trunk, under the cover for the spare, next to the wheel housing, if it is right or left, I can't say exactly, as mine is a UK model, a lot of stuff is reverse from a EU or US model.

There is a switch sitting next to the locking mechanism on the trunk lid, looking like a light switch from a fridge. It has 2 functions, for one it controls the trunk light, but also signals if the trunk is open or closed. So in Hitmans case it seem that it could be an idea to check up on this one. Try to "open" this switch and see if your car think the trunk is closed.

The leads on the locking mechanism are for signalling if the lock has been locked by the key and if so disabling the remote opening of the trunk.

I have seen that there should be steady light in the dash button if the trunk is open, if the system is ok. If it is flashing then it could still be the "Fridge Switch", not "closing" completely, but only just.

You convertible guys, maybe have one more switch, telling the system that the car is not opening or closing the top, and you should try to find that if the above does not help.

Pancho

Was in error re. console switch for trunk release.
Light is solid red, no blinking, when trunk open.

The light/fridge button functions OK turning light on/off.
What else should I look at re. this light/fridge button ?

The actuator is connected to two yellow air lines.
Actuator extends and retracts (see image supra).
What else should I look at re. the actuator and lock ?

What should I look for re. the pump under trunk floor ?
(I always thought the pump was under the driver's seat.)

macclk

The "fridge" button seems to be ok then, the pump seems to be ok, as it activates the vacuum actuator on the locking mechanism. You've got me a little confused concerning the position of the pump, but if it is under the seat, please have me excused.

I would try to imitate the passive part of the locking of the trunk by pressing a rod into the grip of the locking mechanism, push the "fridge" switch and the see if I could pull the rod out from the grip of the lock. I hope you understand where I'm getting.

If this don't work, then I have to give up and can only say it may be the locking mechanism, as the, unless the springs for pushing up and holding the trunklid have gone bad.

Pancho

I'm not sure about the pump location, myself. Somebody told me that a couple of years ago when the trunk went bad.

Good idea re. the rod test on the catch mechanism. Will try that when I get home from work tonight.

PS. Tech friend at the dealership let me into a bay after hours and hooked me up to the Star diagnostic, looked over the error codes, and cleared all the old ghost. He didn't mention the trunk, and I should have asked. Good Harley friend. Cool Star machine. Wish I had one. I think they are $10G or so. Should of had him look for trunk trouble. I've been living with this bad trunk so long that I forgot. I'm getting a knock off diagnostic multiplexer, have software, maybe this will help out.

Whodat

Panch: I'm beginning to think about some kind of diag tool myself. Tired of being at the mercy of these mechanics/techs.

My trunk issue showed nothing on the STAR diag. It was no help.

I still have my old defective trunk lock. I could send it to you if you're in experimental mode. Just let me know. Personally, at this point, I'd just change the trunk lock if I were you.

Whodat

Pancho: I found this old message over on the BenzW website. It's from another guy that had trunk/soft top issues....

"Sorry been over at MBWorld and AMG Private Lounge...

The dealer repalced a faulty trunk sensor...the trunk wouldnt pop at times with remote or inside the cabin. They also replaced the cables for the top. When the top would start to open the front would slam back down and I had to hold it up to keep the bows in bent position for it to close...if you want to discuss further hit me up and I will respond...I have other items I would be happy to share as well...especially my AMG Euro springs...."

Hitman0187

i also need to replace the cables on the top, mine doesnt fall sown when opening but it will get stuck and i have to push it past the beginning stage, and slow it from falling when closing.

i am going to look at that fridge switch this afternoon if i dont get roped into something more exciting. would that cause the trunk light to stay on and toast the battery ?

macclk

It would if the switch doesn't open correctly, when the trunk is closed. And if so then the car would think the trunk is open too, and therefore no reaction when you try to open it remotely or on the dash button.

SoCal208

I do not know much on other model, but on the W208 body, the vacuum pump is in the trunk (face forward), pull of the liner on the right side (up about where the trunk lid met), there is a solf cover (open that soft cover), inside is the vacuum pump (there are many vacuum lines (very small plastic tube) from there it connect to the door lock, rear head rest, trunk release). I was mad because ONE of the rear rest on my rear CLK320 would not fall down (when I hit the head rest on the dash), the SA @MB dealer told me ("there is a vacuum leak somewhere, it's take time to find out where & cost money") (@ the rate $100/hour). On my day off, I pull off the inside of my car to locate WHERE is the leak ?. Inside the soft cover, there are many Y connections, one is broke. I took it out to the dealer,they do not have it, order it for me, a few day later, I got the part, the hard part are : took out the vacuum line out to insert into the new Y vacuum connector, It's too tight to pull it out : I resort to cut the vacuum line as little as I can, put some Vaseline to the tube & insert the tube to the connector, slide it in little by little. After connect everything (before put the liner back), I try it, voila, the head rest WORK, as the door & trunk lock, by the keypad). I hope that it will have fellow Benzo to locate the W208 vacuum pump.

Pancho

Man, that's some good info.
I'm going to try it some time this week.
Would be a blast to get my trunk working again,
without having to give the dealer a bag of gold.

Whodat

Racin_fool

I had a very similar problem with a W208 cabriolet last week. Turned out the car had been involved in a rear end collision at one point. After trying numerous parts and searching wiring diagrams, I found that at some point that someone had swapped the wires plugged into the trunk latch and the 3rd brake lamp. They are both identical plugs except the wires going to them are different colors. Make sure the 3-pin connector going to the trunk latch has a yellow wire in it and not at the 3rd brake lamp connector just above it.

ssc740

just got a clk430 convert, its was a repo, stressed because the top would not move, but learning here, for some reason the trunk latch is missing, dont know why, but I now know that has to be replaced first, before i sweat anymore. (keep hearing about the $2300 pump)