R172 Roof Faulty. Dead.

[cps13]

Hi

My wife’s R172 2012 SLK250 had intermittent operation of the roof for a couple of weeks. She doesn’t drive it much, and the battery was the original. The roof stopped working again, but it was going in for a service in a week, so ask the MB specialist to check the battery, and they agreed the battery was poor (didn’t tell them about the roof) and they replaced it.

Got the car back, roof still doesn’t work.

When you press the button in the centre console to open/close the roof there is nothing. No relay clicks, no dashboard messages, car just behaves like I haven’t pressed the button. On the same unit, there is the button which operates all the windows at the same time, this also does nothing.

I removed the centre console, and tested continuity on the roof and window switches, all seems to work fine. Checked all the fuses in the boot and all ok, clutching at straws hoping it was something simple… I checked all the fuses in the engine bay. All ok.

I have an iCarSoft V3.0 but I can’t find anything in here to test the roof functions. Are there any?!
I tested the roof separator contact switch on the icarsoft and it’s functioning fine. Also don’t get anything up on the dashboard when you leave it open.

I think the next stage is pulling the seats out and the rear panels to get to the hydraulics. But hoping to avoid this if there are other tests I can do first.

Any ideas?

Thanks,

[Doofus]

Is the boot divider thing in the right position?

[cps13]

Yeah. It normally comes up on the dashboard when that’s left open. With it in the open or closed position still nothing.

Also found the test for that contact switch on the icarsoft and it reads it ok.

[Doofus]

Sorry, I got nothing else. Mine is a 208 CLK.

[cps13]

Update.

I’ve pulled the rear panels behind the seats. Probed the hydraulic motor power input, and when operating the switch there is no power to the hydraulic unit.

Tested power to the roof control module and it has 12V coming in. Continuity from the output cables of the control unit to the hydraulic motor.

A used control module is £45. Taking a punt!

[cps13]

Yeah. It normally comes up on the dashboard when that’s left open. With it in the open or closed position still nothing.

Also found the test for that contact switch on the icarsoft and it reads it ok.

[frontfloater]

Google is your friend. There are several Youtube how-to videos covering the common causes of this fault, if you search using "youtube slk roof won't open"

[cps13]

Watched lots of videos, read forums etc they aren’t covering the fault I’ve got.