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MKIII Supras




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Supra Passenger Window Auto Up/Down

So you have cut the little tab off your drivers side window switch yes?  You like the full auto window up and down thing with manual override?  Shame the passenger side doesn’t do the same!....If you don’t know what I’m chatting about look HERE for the auto drivers window mod.

The Following Mod will allow your passenger window to function in the same way with auto up, down and manual override.  It also allows you to do this using the standard factory switch gear as well as allowing the auto function from both the passenger and drivers side switches.

If you hit the switch quickly the window will enter “auto” mode.  If you keep the button pressed for more than 0.5 seconds or while the window is in auto mode, the window will enter manual operation.

So what do you need?  Well you need to get hold of 2 auto window relays from a Ford.  These ones came out of a Mondeo, they are located in the drivers side door to operate the one touch down.  Make sure you get the 4 wire versions of the relay as shown here.

There is only one relay per Mondeo so, you’ll need to find a junk yard with a couple of cars or search on Ebay for “one touch relay”  There are normally a few about, other fords probably use them too so shop around, should only cost you about 5.

Auto relay (300 x 188)

To fit these into the Supra you will need to remove the passenger side door card completely and take out the speaker pod.

Below you will find a circuit diagram with the Supra wire colours in BLACK and the Relay wire colours in GRAY along with the relay pin numbers incase you don’t want to use the Ford relay sockets as, standard spade crimps can be used.

Pass Window Auto

Make sure you get the wires round the correct way when splicing into the car loom. ie: the motor side of the red wire goes to yellow/purple of the relay and the switch side of the red wire goes to the yellow/green wire of the relay and so on.  Do this with the ignition OFF people!!!!

You can join the two black relay wires together.  These will need to attach to a suitable earthing point such as the one below.  The two purple/orage wires need to splice into the blue wire on the car.

If you would like more information on the Supra window wiring, it can be found HERE.

Auto window 002 (400 x 305)

<---- Earth Point - Existing Bolt


Click for larger image.

I cut the tags off of one of the relays and made a bracket to join the two together.  This saved space and allowed for just one mounting point.

Once fitted and wired check the relays dont catch on the bottom of the window glass, it runs close so positioning needs to be careful and secure.

The relays can be mounted in a spare module space in the passenger door, just behind the speaker pod.

This is a great place to mount the relays as not only is there plenty of room for them but, the electric window switch wires you need to interface with are there too, often run in a piece of black plastic.

You can see here where I have fitted the relays and routed the wires including a good earth point to pick up as, there is not one in the loom.

You can either zip-tie the relays in position with the hole already in the door or drill and screw them down.

Auto window 001 (300 x 151)

The following information is important should your relays NOT TURN OFF automatically. 

Because the Mondeo window motors are slightly different to our Supra ones some relays wont turn off strait away when the motor comes to a stop.  If this is the case with your relays you need to do the following Mod:

Auto pcb (300 x 183)02

Click for larger images

Auto resistor (300 x 172)

Open up the relay by pulling it out of its case with a pair of pliers.

Locate the two solder pads circled here and fit a 3K resistor between the two points.

This changes the trip limit of the circuit and brings it to that of the Supra motors so the relay switches off when the motor comes to rest up or down.

I did this mod to the relays I fitted anyway as a precaution to prevent the motors staying on when stalled. 

If your relays don’t work at all then the ground point in the door is probably bad. 

The doors only earth through the hinges so, don’t always get a good ground.  To solve this  problem you can run a wire through the door cable rubber and earth one side to the door chassis and the other to the car chassis behind the passenger kick panel.

If all the above has gone to plan you should now have fully automatic passenger windows:)

I don’t see any reason why this system could not be adapted to any vehicle with a similar switching arrangement i.e: motor normally grounded with switched lives.  The resistor may need tweeking for other motors to switch the relay off correctly...suck it and see, always worth a shot.

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If you found this guide helpful or have a comment, please sign my Guest Book or use the Message Board.