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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53943
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I am looking fuse location vario-roof hydraulic pump on a

Customer Question

i am looking for the fuse location for the vario-roof hydraulic pump on a 2003 sl500. I just replaced the roof latch cylinder and paused the top mid cycle to do an inspection and now the pump doesnt operate when buttons pushed and no codes have come up on a system scan.
JA: Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: like i said i was doing a cycle of the top to bleed air after a cylinder replacement and i stopped it mid cycle to inspect for line pinching at a hinge point. and now the pump wont operate and the dash just says still in operation. so I do not want to reach into the trunk and mess with the relay and risk injury. i am hoping the fuse is in a different fuse box elsewhere in the vehicle
JA: Is there anything else important you think the Mercedes Mechanic should know about your Mercedes?
Customer: no i just need the fuse location for the roof pump
JA: I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and connect you two.
Submitted: 1 year ago.
Category: Mercedes
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Marty replied 1 year ago.

Hi, fuse 73 in the rear fuse box behind the passenger seat is for the hydraulic pump motor. I've attached a picture below.

Customer: replied 1 year ago.
I had already located that by the time you responded. The all of the fuses for the vario roof are operational. I tested power and ground on white and block wires to pump while peeking my head into the trunk since the top isn't all the way down in there and the trunk is still opened. I got ground on both wires and neither would switch to power when I operated the switch in the car. The switch just blinks and there's no pump noise. Reviewed data stream in scan tool and can only really see "position and function of limit switch" as only parameter not saying ok. Voltages and fluid temps are ok.
Expert:  Marty replied 1 year ago.

Have you scanned and erased fault codes?

Customer: replied 1 year ago.
I have cleared the vario roof control module codes since the roof froze. There were no codes prior and still none set since. I am going to try unplugging the pump again like I did to move it for access to the lines.
Expert:  Marty replied 1 year ago.

It's possible that the pump overheated but you should be getting some sort of fault codes. I'd try manually raising the roof and see if it will operate after you move it.

Customer: replied 1 year ago.
I just pulled the top up to the windshield but I can't force it into the latches at the windshield so therefore I can't try and fully close the trunk. In the almost closed position now it still isn't turning the pump on.
Customer: replied 1 year ago.
Is there a way to manually over ride the relay and just power and ground the 2 large wires going into the pump to see if it will at leAst run with a power probe? There's 2 large wires and a few very small ones for temp and stuff I'm sure.
Expert:  Marty replied 1 year ago.

Sorry for the wait I was off work on Friday and completely missed your reply. Yes you can briefly bypass the relay to see if the motor runs. Remove the relay and jump from terminal 30 to 87 in the relay connector plug and the pump should run.

Customer: replied 1 year ago.
I did all of that. Got motor to run easily and then released system pressure and got top closed and reset and it operated but had trouble with the latching portion of the sequence so I assume I reversed the latch lines maybe. But more importantly on one test cycle it stopped mid cycle and now I can't force it forward or backward even though pressure relief is opened and no diagnostic tool is connected so it's not in diag mode. I don't think it's far enough to the point to be in the range where it expects the flaps to move bc I had it get stuck before in the load assist position and closing flaps allowed it to move but that's not happening this time.