450 Glass Sliding Roof Wiring

The wiring for the glass sliding roof is very simple. Actually running the cables takes the time.

Both of the connections to the SAM unit are switched lives. Both connected to 15A fuses. R1 is an auxiliary fuse on the side of the SAM unit. Plug 3 pin 4 is the power for the switch but it is also the power for the stereo and the speedo. You could connect this cable to R1 also.

To make my life easier, I was supplied a wiring loom from a car that had this type of sliding roof. So it was just a case of removing the sections of wiring loom that I needed.

I found the 2 connectors that went up into the roof and marked them so I didn’t lose them.

This is what the 2 connections looked like.

On the other end of these wires was a 6 pin connector. This connects to the roof switch later on.

I removed the wiring I required which wasn’t very much.

To keep it looking standard, I used a cabrio roof switch.

Luckily, I had the car apart so I laid all of the wiring out, quickly connected it up and tested it.

It worked properly. So now it’s time to run all of the wiring.

In the back of the roof you’ll have a few holes. I ran my cables through the one shown.

The problem is that the wiring has to emerge into the space where the rear left light is. Getting your cables down there is quite tough. What I eventually did was to push thick cable down from the top…

…and then tape my wiring to it so I could pull the wiring up from the top. Connect both connections to the roof motor.

The rest of the wiring can then be routed into the boot with all the existing cables.

Just below the exit into the boot is an earth point perfect for the brown wire.

The other 3 wires should be run forwards, towards the centre of the car and down the centre.

To keep things neat I removed the SE drive so I could run the cables underneath it.

There is plenty of room to spare. Just tape down the new wires so they are secure.

The 6 pin connector goes over to the passenger’s side where the switch will be.

I put everything back in the car and refitted the SE drive.

The SE drive cover has a plastic disk on each side.

Pull off the side where the switch will be placed.

Run your cable through the oblong hole. I messed up a bit as I hadn’t left enough wire so I made the hole bigger.

Connect the wiring to the switch, push the switch housing into the SE drive cover and twist it forwards to lock.

You are now left wire 2 wires. In the wiring diagram at the top of the page, these are:
1.5 mm2 Red/Green to R1 (switched live)
0.75 mm2 Blue to SAM plug 3, pin 4.

To make it easier, you can just connect both to the same auxilliary SAM fuse at position R1. (15 Amp fuse). Or, if you want, you can fit another auxilliary fuse and push it into R2, R3 or R4.

They are all the same switched live connections. Or, if you want the roof to operate even when the ignition is off, you can just connect both of these cables to the battery + connector. (this is what I did in this car).

What If I Don’t Have An Old Wiring Loom?

You’ll have to cut the connections off the roof motor and crimp your own wires on. Or, if you do some research, you could try and buy repair connectors from smart. The hard part here is getting the VIN code from a car that has this roof from the factory so you can get the right connectors shown on EPC before you can find the right 3 that you need.

The connector for the cabrio rof switch is the same on the standard cabrio so that should be easy to get.

Can I Make My Own Roof Controller?

I fitted the roof years ago and now I really don’t understand how the old wiring worked. So, it’s just easier to ignore the standard wiring and make your own controller. Obviously the motor only has 2 wires but the switch will have 3 wires.

Common input.
Ouput 1.
Output 2.

However, in this layout we are using the switch backwards.

Common output.
Input 1.
Input 2.

You just need 2 standard automotive 5 pin relays and the standard smart roof switch. Sorry for the hasty drawing. If it doesn’t make sense, let me know and I’ll draw it properly.

This circuit earths both motor wires but switches either side to power as you operate the switch.