Owning a convertible vehicle can be fun and exciting until you start experiencing problems with the convertible top. One day, you press the top switch in the center console, and nothing happens.
The convertible top won’t go down. If lucky, you can open the convertible top by pressing the switch several times.
This article will show you how to troubleshoot some of the most common convertible top problems. Convertible tops can seem complicated, but the hydraulic system is straightforward, regardless of your make and model.
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All hydraulic convertible top systems function practically the same, whether you own a Mercedes-Benz convertible or a Mazda, Chrysler, Toyota, Porsche, BMW, or Lexus.
Determining and fixing the problem requires patience and knowledge of convertible tops.
Common Convertible Top Problems
- The convertible top won’t open or close.
- A bad fuse, relay, top motor, lift cylinder, etc can cause it. Read this article to find out.
- The convertible won’t move or get stuck
- Broken cable or lift cylinder
- The convertible top won’t go up / down
- The same causes are described above.
- The convertible top moves very slowly.
- A weak lift cylinder often causes it.
- It can also be caused by binding or convertible motor failure.
If a convertible system may seem complicated initially, don’t let fear stop you from performing a few basic troubleshooting steps yourself.
This troubleshooting guide provides instructions and detailed steps to follow if you are experiencing problems with your convertible top.
If you have any tips that we may have missed, please add them in the comments section to help future readers.
Why does a convertible stop working?
Let’s look at the most common problems that cause the convertible top to operate properly.
- A defective, bad switch,
- Convertible top motor (pump),
- Weak lift cylinders
- Binding in the mechanical parts,
- Blown fuse or bad relay
Double-check the instructions in the owner’s manual if you can’t get your convertible top to go up or down.
Next, perform a visual inspection of the top to ensure no fluid leaks or broken cables.
Troubleshooting Convertible Top Problems
To troubleshoot your convertible top problem, we assume you know how to locate and check fuses, relays, and convertible top components such as lift cylinders, convertible modules, and pumps.
If you are having trouble finding these parts, visit your dealer; most dealership parts departments are kind enough to print the convertible top diagram for free.
- Digital Multimeter
- Lithium Grease
Trunk Compartment Divider
Pull the divider from its stowed position and hook the pins into the brackets. The trunk compartment divider ensures enough room to lower the top into the trunk. The convertible top won’t operate unless the compartment divider is in the correct position.
One of the main problems preventing the convertible top from going down is the micro-switch that detects if the compartment divider is pulled/engaged.
The switch for the cargo divider fails frequently. Use a multimeter to test this switch. If it has failed, replace it with a new one. These switches are inexpensive and can be purchased from your dealer or online. Watch this video on how to test convertible switches using a digital multimeter.
Check convertible top fuses and relay.
Checking the fuses is easy, and you can complete this step yourself. Locate the fuse box and look for the convertible top fuse.
Depending on the model, the fuse box is located on the dashboard’s side or under the hood in the engine compartment.
Pull the convertible top fuse. If the fuse is blown, replace it and check if your convertible will operate normally. If the fuse is ok, check the relay. The relay can not be inspected visually, but there are ways to test them.
You can locate an identical relay in the fuse box (keep a note of which system it serves) and swap it with the convertible top relay. If the relay and the fuse are not the problems, move to the next step.
Check the convertible fluid level.
A considerable number of convertible top problems are caused due to low hydraulic fluid levels. If the level drops below the MIN, the convertible top will either not operate, move too slowly, not close, or stop halfway.
Locate the convertible top motor. In most convertibles, it is located in the trunk behind the lining. Also, check near the spare tire or behind the rear seats. Looking at the fluid reservoir, you should see a MIN and MAX on the side. MAX, in some cases, is not marked because it is the same as the fill hole. You can’t fill them past the filler hole since the fluid will leak out, which is by design.
Suppose the fluid level is too low to completely protect the motor and the hydraulic system components for the convertible pump operation. Sometimes, the pump does work, but air may be introduced into the hydraulic lines. In return, insufficient pressure will be built up to operate the convertible up and down. If you suspect air in the system, it operates the convertible top three to five times to get the air out of the lines. Recheck the level.
Check Convertible Pump Operation
The following video shows a convertible top motor running. Pay attention to how the pump sounds. While the pump runs, the hydraulic system has air trapped in the lines.
Also, this system has a major hydraulic fluid leak, so the level drops below the MIN mark. As the level drops, the convertible struggles to move up and down.
Check the operation of the convertible pump motor. Turn the ignition on but the engine off and press the convertible top switch to retract the top.
Check cylinders for fluid leaks.
Another common reason convertible tops fail to operate is a leak at convertible lift cylinders. The hydraulic cylinders move the hardtop or soft top up and down. They have seals and o-rings that shrink and crack due to age.
When this happens, they start to leak, and over time, the convertible top fluid drops below the required levels, and the convertible stops working. You can visually inspect all the cylinders for leaks by manually opening and closing the convertible.
At first, the leaks will be minor, but they will worsen over time, and you will eventually see leaks on the trunk floor or a stained convertible top. Have a friend help you during this process so the top doesn’t fall on you.
Find out how many cylinders operate your convertible top. Scrutinize all of them for any fluid seepage. Convertible top leaks are quite obvious, but they may be difficult to locate in the early stages.
When your convertible top stops working, the leaks should be easily identified. Inspect the hydraulic lines. Make sure they are tightly connected.
The hoses should not be cracked or leaking. Address any leaks that you may find at the pump, cylinders, or solenoid. Replace any damaged or leaking o-rings.
You can get an O-ring assortment kit online and replace any damaged gaskets. Lift cylinder gaskets can’t be replaced easily, and either need to be replaced or be sent to a shop that does convertible top repairs.
They can often refurbish them.
If you have a minor leak, you may be able to get away with just adding hydraulic fluid. Ensure to use the recommended fluid, and don’t use brake or power steering fluid if not approved by the manufacturer.
One of the most commonly used convertible top fluids is the Pentosin CHF 11S.
Verify that the convertible top motor is getting power
Use a digital multimeter to check the lines feeding the convertible top motor. Every time you press the convertible switch, you should read between 11-13 volts at the pump.
If you are not getting any current at the hydraulic motor, you may have an electrical problem or a defective switch.
Inspect the microswitches
Between 4 and 10 micro-switches are installed in your convertible required to run your top. If one of them fails, your top will stop working.
Check for binding
The last step is to operate the convertible so that you can inspect it manually. Look in your owner’s manual for instructions on how to operate the convertible top manually.
Almost all convertible tops can be operated manually if the automatic top operation fails.
Operate the convertible top up and down a few times and inspect for binding as you do this. You may find that a bent arm or a broken cable stops the top from operating properly.
Make sure that joints that move are lubricated. Excessive friction can overload the pump, which can cause the convertible top fuse to blow.
Check the hinges and linkage and compare the left and right sides.
Make sure they are aligned properly. There shouldn’t be any loose linkages or broken cables.
Apply lithium grease on the joints, pivot points, and cable.
We hope that this guide helped you troubleshoot your convertible top problems. If your top doesn’t work properly, you must identify whether the problem is mechanical, hydraulic, or electrical.
Follow the steps in this guide to eliminate some of the most common convertible top problems.
In most cases, convertible top problems are either caused due to electrical problems or low hydraulic fluid levels caused by a leak.
Remember that the Power Top Control Module (PTCM) (Convertible Top Control Unit) monitors and controls the convertible top’s lowering and raising.
A series of micro-switches verify that operations are complete before allowing the next stage of lowering or raising operations, such as deck lid unlock, convertible top fold, deck lid open, and deck lid close.
Hydraulic convertible systems use the same principle regardless if you drive an Audi, Mercedes, BMW, Porche, Lexus, Mustang, Chrysler, or Mitsubishi Eclipse.
Let us go over the list of most common convertible top problems:
- Low Hydraulic Fluid Level
- Failed convertible top pump/motor
- Broken or bent top armor cable
- The low fluid level in the top pump reservoir
- Poor Ground Connection
- Air in the System
- Weak Cylinders
- Defective micro-switches
Buying Convertible Top Parts
Don’t spend a fortune on convertible top parts. If you need replacement convertible top parts, you can find new and used ones online at a fraction of dealer prices.
We hope you find the Troubleshooting Convertible Top Problems guide helpful. Check these troubleshooting and repair guides for more help on your vehicle.