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After trying to put the top down, hear clicking in the back and nothing else happens. Button flashes slowly after a few seconds.
- Compartment cover hydraulic cylinder leaking, fluid in resevoir slightly low. Replaced cylinder with a used one and refilled tank. No change.
-Checked fuses, all good, not blown.
-Swapped pump relay with fuel pump relay. No change.
-Checked voltage at pump relay base, pin #2. 0 volts.
-Checked voltage at connector to the relay base. 12 volts.
-After reseating connector plug, rechecked voltage at relay base pin #2, now there is 12 volts there. Hearing longer duration of clicking but still not working.
-Rechecked voltage at relay base, 0 volts again.
-Cleaned connector both sides. Still not working.
-Rechecked voltage at relay base, 0 volts.
-Rechecked voltage at connector, 0 volts.
-Checked voltage at fuse #13, 12 volts.
-Took another look at fuse #13. It was very hard to pull out. Looks like it had an arcing spot and maybe a little corrosion on both sides of one leg of the fuse. This was probably causing an intermittant connection especially with a load applied.
- Replaced fuse with a different one. Top working normally now.
Here's what the leg of the fuse looked like (after I tried to clean it up) and a schematic to use if you're having the same problem.
03 SL Kleemann, 97 SL320 pano top, 95 Lorinser E320 Cabrio, Ferrari 360, Tesla X
convertible top fuse, relay, pump, and cylinders
marko69,
nice find, and I like the title of your thread! Looks like corrosion on the fuse caused the problem. I have heard about this a number of times on early model R129s (SL-Class), where dissimilar metals between fuse and fuse holder caused the same problem, but this is the first such report that I am aware of on a W208 CLK cabriolet.
In most cases when the pump won't run at all but the relay next to the pump is okay, it is a burnt out electric motor in the pump. When Top Hydraulics rewinds the electric motors in the pumps, we actually put some 50% more copper into them. The heavier gauge wire in the motor will not heat up as quickly and will thus allow the fuse to trip before the motor overheats and melts inside. Of course, there is a lot more that we do to the pumps when we rebuild & upgrade them, see http://www.tophydraulicsinc.com/en/w...ulic-pump.html.
You replaced a leaking hydraulic cylinder with a used one. Maybe you are on a really tight budget, or you are planning to sell the car. I don't mean to be negative, but do you really think a used hydraulic cylinder will last long? Any hydraulic locking cylinder with original seals that is more then ten years old and not leaking yet, is a case of luck. Top Hydraulics upgrades all seals in these cylinders, and they should last about three times as long as brand new ones under the same circumstances.
Just for completeness, the pump relay part number is A 002 542 13 19, and below are the part numbers that apply to the pump: 2088000030 aka A 208 800 00 30 (model years 1998 - 2000, up to VIN -070017 in model year 2001) 2088001048 aka A 208 800 10 48 (model years 1998 - 2000, up to VIN -070017 in model year 2001) 2088000230 aka A 208 800 02 30 (model years 2002, 2003, and from VIN -070018 in model year 2001) 2088001748 aka A 208 800 17 48 (model years 2002, 2003, and from VIN -070018 in model year 2001)
marko69....Congrats on posting yet another inexpensive DIY power roof repair. Your trouble shooting skills were spot on and feedback impeccable.
The operation of the power roof is very complex and depends on a micro-controller, hydraulic pump/electric motor/relay, 7 hydraulic cylinders, a dozen plus limit/position switches, pair of tension cables, wiring harnesses as well as other subsystems (e.g. roll-bars, power windows, closed and locked) all being in proper working order.
The design mean time before failure (MBTF) is 10 years and with the W208 average age being 15 years old, it's not a question of 'if' it will fail, but 'when' it will.
As a result, you will find numerous threads pertaining to trouble shooting and repair of the power roof system. The most common issues have been with leaking hydraulic cylinder seals (particularly those operating the unlock/lock soft top cover and rear bow) and pump motor relay. Fortunately the cylinder(s) can be rebuilt by Top Hydraulics, using better seals than OEM. Also, the W208 section at their web site, has a DIY link that covers how to access the power roof components etc..
The motor starting relay frequently fails because it's contacts switch a lot of current (e.g. about 30 amperes). Every time the contacts make and break, arcing causes contact pitting, which over time builds higher resistance to current flow and insufficient power to run the pump motor. Note: In some cases, the contact arching has also caused the contacts to weld together, causing the pump motor run continuously, which will burn or short out the motor if the thermo cut off does not operate properly.
The OP said when attempting to operate the power roof, he heard clicking. What this meant is that the micro-controller had successfully looked for and verified all of the early stage required conditions to start operation of the power roof (e.g. the clicking was the controller activating the relay's control coil circuitry).
Referring to the electrical diagram in the initial post, the battery (labeled G1) supply's power to operate the roof through several fuses. Specifically, in fuse block F4, located inside the trunk behind the battery, there are 2 fused circuits. The circuit to power the controller is provided through a 15A fuse at position #11. Additionally, at position #13, there is a 40A fuse, dedicated to power and protect only the pump motor. Summary: at this point, the controller was trying to activate pump, which remained in-operational.
Tracing out the fuse 13 circuitry, from the battery, it's a series connected circuit of cables, fuse, relay contacts and motor. A defect in anyone, would cause the pump to not operate. Note: Think of a string of XMAS lights, where one bad bulb will cause all the bulbs not to light.
Possible problems?
1. In the W208, there are 3 positive battery cables attached to the battery. The small black cable feeds the aforementioned F4 fuse block that powers the roof. IMHO, should not be a problem.
2. The relay's contacts have pitted. While common, the OP already tested via substitution with fuel pump relay. Additionally, in other thread posts, Top Hydraulics showed to to test using a jumper wire.
3. Burnt out motor winding causing the open circuit. Hope not $$$$$$, but there are ways to prevent (e.g. pull fuse 13).
4. Bad fuse.
Enclosed is the location of the F4 fuse lock and the assigned fuse locations.
Last edited by Serndipity; 02-13-2015 at 08:50 AM.
02-11-2015, 01:04 AM
