Mercedes Convertible Problems, Troubleshooting, Fixes

Owning a convertible Mercedes-Benz is fun and exciting until the convertible top stops working. If you own a hard-top Mercedes convertible such as the SL-Class and SLK-Class or a soft-top convertible such as the CLK / E -class and are having issues with the convertible top, this article may help you.

Mercedes Convertible Top Won’t go up or down
Convertible top moves very slow

Common Causes of Mercedes-Benz Convertible Top Problems

Mercedes Convertible top moves very slow

This can be caused by low fluid levels or air in the hydraulic lines.
Air in the hydraulic lift cylinders
The binding of mechanical arms can cause it.
Weak convertible top lift cylinder.
Weak battery or ground connection.
Leak at the o-ring at any of the lift cylinders.
- Bow tension cylinder (driver or passenger)
- Main lift cylinder (left or right)
- Tonneau cover cylinder
- Rear bow latch cylinder
- Storage cover latch cylinder

Mercedes convertible top won’t go down or raise

Convertible top pump/motor defective
Bad convertible top relay
Low fluid
Defective divider microswitch
Transmission not in Park / Neutral
The switch at the center console is faulty
Convertible top fluid leak
Inspect the trunk area for a hydraulic fluid leak.

The Mercedes convertible deck doesn’t move

Low fluid in the convertible top reservoir.
Deck lid lift solenoid defective
Decklid micro-switch defective
The hydraulic pump is not working
Soft top bow open/closed switch broken
Frozen or stuck mechanical arms or broken cable

Troubleshooting Mercedes Convertible Top

Start by pressing the convertible switch. Do the windows go down?
If the windows don’t go down, make sure the trunk compartment divider is pulled out.
Next, check the fuse for the convertible top. This is usually a 40 A fuse. If it is blown, replace it with a new fuse with the same ampere rating.
Check the convertible top relay as well. Swap it with a known working relay that is identical. You can also bridge the top relay for a few seconds to see if the hydraulic pump starts running. Replace the convertible top relay if necessary, PN 0025421319.
Next, check the micro switch where the divider locks. Do you know that trunk separator that you are supposed to pull out and engage it in this hook? It is supposed to press this little switch. Inspect it first.
You can unplug the wires going to the micro-switch. These switches should be tested for proper operation by checking continuity when the switch is pressed and when it is not. You can follow this more in-depth guide on Troubleshooting Convertible Top problems.
Check the convertible fluid reservoir. Is it below the minimum mark?
Check for oil leaks at the lift cylinders if it is below the mark.
Add convertible fluid.

How to add convertible top fluid on a Mercedes-Benz

To add hydraulic fluid to your Mercedes-Benz convertible top reservoir, you will need the following:

A new syringe
13mm socket and ratchet
Mercedes Convertible Top Fluid Pentosin CHF 11S Synthetic Fluid is often used without the OEM Mercedes hydraulic fluid. Check for compatibility in your owner’s manual.

Instructions on how to add Mercedes convertible top fluid:

Locate the convertible top motor in the trunk. In most Mercedes-Benz cars, including SL, SLK, and CLK classes, it is located in the trunk left or right side. You will need to remove the trunk lining to see the reservoir.
Remove the 12mm bolt from the reservoir.
Use a clean syringe to add fluid to the reservoir.

Hopefully, by now, you have pinpointed the problem. The convertible top operation may be failing due to a problem with the N10/3 (combination control module), which is the module that controls the convertible top.

Conclusion

Troubleshooting Mercedes convertible problems can get very complicated and expensive. That doesn’t mean that you can’t do a few check yourself, such as checking or replacing the convertible relay or adding fluid. Most Mercedes convertible problems are caused by a bad relay, weak lift cylinder, or lift cylinder leaking by the o-ring. If you find out that the convertible top reservoir is low in the fluid, you have a leak, most likely at one of the convertible lift cylinders. It may be a very slow leak but you need to add Mercedes hydraulic fluid for the convertible top. If the fluid in the hydraulic unit gets too low, the lift cylinder may suck air and cause other symptoms such as a slow convertible top operation. Have a convertible top professional replace any lift cylinders or o-rings that may be defective.