One Touch Electric Windows

One of the day to day features I miss from the Defender is the ability to close the windows with one touch of a button. The Defender highlights this omission because it is necessary to reach across to the other side of the centre console to press and hold the switch until the window is fully closed.

To solve the (admittedly first world) problem, I have sourced a DEI 530T Window Automation System which provides one touch operation of the electric windows and auto-closure when locking the vehicle.

The DEI 530T instructions list 3 different types of window switches that it can be configured for (Type A, B & C). The Defender uses the Type B configuration, this means that both wires going to the motor are held at the battery voltage when the motor is at rest. To move the window up or down, one side or the other of the motor is pulled to ground by the switch to allow current to flow.

To begin, the centre console was removed to gain access to the electric window switches:

 

The pictures below show the factory electrical connectors.

 

 
According to the instructions for the DEI 530T, the wires between the electric window switch and motor should be cut to allow it to be wired in, however I do not like to make any irreversible changes to the Defender unless it is absolutely necessary. 
Fortunately, defender2.net user PaulMc was able to supply me with AMP connectors that use the same crimp terminals as the factory electrical connectors.

To avoid damaging the loom, the crimp terminals were released from the existing connector:

 

 

 

The crimp terminals were then clicked into the new AMP connector housings

 

 The mating connector for the AMP connector was then used to make a small extension loom that would allow the DEI 530T to be wired in.

 

  

The loom was made off with crimp terminals which were clicked into the original connector housings for the electric windows.

 

 

The following pictures show a close-up of the wire colours on the extension loom. The Red/Orange wire on the switch connector is for the illumination of the switch, a tap was taken from this wire to be used or future projects that require a signal when the lights are on.

In order to power the DEI 530T, some wires had to be pulled into the dash from the auxiliary fuse and relay box under the cubby box, so the opportunity was taken to pull in several wires at this time that may get used for future projects.

 

 

The following picture shows the wiring behind the centre console completed. The mate-n-lock connectors at the bottom of the picture were used to extend the battery feed and auto-closure control wires. 

 

Double sided sticky tape was applied to the back of the unit to mount it inside the dash.

 

The mounting position is shown here in 2 perspectives:



 

 

The DEI 530T requires 3 main wires to be earthed, the main power for the control unit and a ground return path for each electric window motor.

 

Using a wooden skewer, the earth wires were drawn through the large oval grommet on the passenger side of the bulkhead.

 

  

The earth wires were accessed from inside the passenger compartment via the access hatch on the passenger side of the dash.

The main ground wire for the DEI 530T was crimped and extended inside the dash using a bullet connector with an insulating sleeve.

 

All 3 earth wires (along with a 4th spare wire) were drawn through the bulkhead grommet to the engine compartment.

A earthing point is available on the bulkhead a few inches across from the oval grommet.

Each of the earth wires were tinned using solder, to reduce the possibility of corrosion, and then crimped with an M6 ring terminal.

The wire ends were then covered in heat shrink for further protection.

 



All four earth wires are shown here on the earthing point with the factory wiring.

 

 

 To enable the auto closure feature on the DEI 530T, a "ground-when-armed" output is required from the alarm system. I don't know if this is available on the Defender, but DEI recommend using a normally closed relay activated by a negative lock pulse from the security system.

My implementation is slightly different than suggested in that the relay coil is permanently wired to ground rather than +12v with the lock pulse on the orange wire energising the relay to momentarily release it from ground. 

The wires for the door locks can be accessed in the seat box under the drivers seat. On a 90, the plug is not connected to anything as it is to allow an extension loom to be plugged in for second row doors in a 110 or 130.

Again from defender2.net user PaulMc, I acquired the mating connector housing and crimps to allow a tidy connection into the factory loom.

 

The normally closed relay is shown here in the auxiliary relay box. The yellow 20A fuse at the top left of the auxiliary fuse box is the main feed to the DEI 530T.

The finished installation is completely invisible once the dash is reassembled.

A rough sketch of the wiring diagram can be seen here with some relevant references to the Defender wiring diagram:

 

The relay at the bottom right of the schematic is not necessary but has been included for completeness. The DEI 530T seems to be flawed when using the Type B configuration, in that the electric window switches stay functional even when the ignition is off.

By cutting the earth from the switch when the ignition is off, normal operation can be restored. It's probably not essential for security purposes since a window would need to be broken in order access the switches, defeating the point of using them.