2003
83,000 miles
coupe

When I go over 90mph the car starts beeping because the spoiler won’t come up, when I press the spoiler button nothing happens, I believe there’s supposed to be a flashing red light on the button to tell you it’s not working but I don’t even have that, no flashing red light - spoiler doesn’t automatically rise up - and the spoiler button doesn’t work,

when I first got the car the BAS/ESP light used to come on and off every so often but it hasn’t come on in months

I’ve checked the 10A fuse and seems fine and done the BAS reset where you full lock the steering each way also no lights on dashboard or OBD codes,

could it be an electric problem or something causing this? is there anything else I could try before buying a new spoiler motor.

Thanks.

 

before buying a motor, remove the plastic from the hatch and get at the wing. Apply 12v dc directly to that motor and see if it's bad: look at the rotating gear and inspect the cut on/off switch. Remove the rubber boot at the top of the hatch and inspect the wire for a break. While you are there and at final reassembly be sure to reseal the wing plate with "MoreTite" or similar sealing caulk.
There may be a problem with the Body Control Module (BCM), wheel speed sensors, or the ESP/BAS module which may or may not set a warning light. Getting a diagnostic scan from an appropriate tool that gets beyond just OBD codes will get you headed in the right direction.

 

Check and lubricate all the hinged points and gears

 

I disconnect it and cleaned all the connections, it went up past 60 but doesn’t go back down, the button doesn't work either and no light at all when I press button

 

CurtCrossfire
How old is your battery? Do you have any documents informing you when it was installed? The electronic are very sensitive to any low output in the battery. If the output is less than 12 volts, buy a new battery.
Dennis
DTMenace

 

Battery is new had it tested couple months back and is working at full capacity

 

You cleaned what? Did you have the plastic off of the hatch so you can get at the motor? Did you inspect the limit switches? Check the linked thread for additional info. The limit switches are Crossfire specific parts so they are no longer available but read down to post 15 for part replacement and post 18 for a "fix", spoiler info/help

I'm not sure that you may have a problem with a wheel speed sensor. A good scan would help with that possible issue.
Good Luck

 

Wrong. What appears to happen, is the battery loses some of it's capacitive reactance and becomes less of a filter. It is NOT always a matter of capacity or voltage that is causing the BCM / ABS to have a fit and not operate the wing properly. Load tests do not show this, it can still be your battery.

But I'd also suspect a wheel speed sensor OR one of the limit switches on the wing mechanism in the hatch lid. In rare cases, it's pitted contacts or flaky solder joints on the RCM.

LOOK, it's hard to troubleshoot YOUR car when WE are not standing there. Consider this:
WE ALL should be carrying a spare crank sensor and RCM. I carry both. Consider ordering a new RCM andputting it in. If that clears the issue, send the old one to DJ for reworking. If it does not fix it, you have your spare RCM for when the RCM fails in the rain on a highway as you coast to the side of the road. It is money well spent.

RCMs plug in without tools, ANYONE can change one with NO SKILLS and NO TOOLS. The RCM causes many issues: No start but crank, no start and no crank, P401 error, ABS failures, etc. DO NOT order a Crossfire part - order a "Mercedes 2003 SLK320 Relay Control module". I accidentally ordered a "2003 Mercedes SLK230 relay control module" and it worked as well, it is the same unit but one fuse is the wrong rating - didn't seem to matter.

 

when I have this plugged in and I press the switches the motor dosent move does that mean I need new switches? As the motor works because it goes up when driving past 62mph

 

Those are LIMIT switches, they STOP the motor from running when the wing gets to the upper or lower physical limit of travel. You use an ohmmeter to determine if they are opening and closing properly.
The switches should have labels on the pins:

NC- Normally closed, connected to "C" when not pressed,open when not pressed.
NO- Normally open, not connected to "C" when not pressed but connected to "C" when pressed.
C- Common

They send grounds to the BCM to tell it what position the wing is in. Remember, the BCM operates the wing, based on presses of the console switch or based on speed data from the brake controller. You wont likely fix this without the service manual and understanding how it all works.

 

Why does everyone keep saying 2003 SLK320? Nothing changed with the 2004 SLK320 it is the same as 2003 model.