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MKIII Supras




Cygnus Tech

Groupama Saga

On some Supras it’s not possible to have the side lights come on without the headlights popping up and coming on dimly once the ignition is switched on.

This is called a Dip-Dim system, it was a safety idea in the eighties to increase a vehicles visibility in towns at night.  What it actually achieved is most people forgetting to turn their headlights on properly in the first place hence, manufacturers sussed it was a very silly idea and dropped it.  Trouble is this left a few random cars built in this period with the feature fitted but, because it was not around long little or no documentation exists.

The following mod will disable this system completely allowing you to control all lights independently so, you have the choice of having just the sides on without the main lights popping up - this is what most supras do in the first place. (Based on UK NA spec car) 

Relay locations (550 x 338)02

Disabling this system involves the removal of 1 wire from the Dip-Dim Relay plug.  The module is a green box mounted on a bracket between the Brake and gas pedal.

To gain access to it, remove the plastic trim above the pedal box, this has 6 screws fastening it - remeber 2 of them are hidden behind the hood release lever.

Dip-Dim Vent Fitted (150 x 97)
Dip-Dim Location (150 x 137)

Once the trim is removed you will be confronted by a black air duct, its easier to do this job if you remove this.  Simply push it over to the right and pull down on the left hand side, you should find it just pops out fairly easy, its only a push fit.

Once this is removed you should be able to locate the Dip-Dim module mounted to a bracket Between the brake and gas pedal - you won’t need to remove the unit from the bracket, you will just need to unplug it from the loom.

You may think, great!  We can just pull the plug on this but, this is not the case as the headlight controls feed through this module so it needs to stay in circuit.

Dip-Dim Module (250 x 213) (150 x 128)
Dip-Dim PCB component side (250 x 179) (150 x 107)
Dip-Dim Plug pins Jpg02

Because this module needs to stay in circuit we need to remove the IGNITION command to it.  This way when the side lights are on and the ignition is turned on the module won’t get the command to switch on the Dip-Dim mode thus, your lights wont pop up and switch on dimly.

The wire we need is the yellow wire on pin 2 of the connector. 

Dip-Dim Plug (140 x 138)02

This yellow wire is the control input to the dip-dim system.  To disable the system simply remove this connection from the plug.  You can either cut and insulate both parts of the wire or, the better option is to remove the pin entirely from the plug and insulate it.  This way the system can be reinstated easily and prevents random cut wires wafting about - never good!

The pins are easily removed with a very small flat bladed screw driver. 

Look into the pin side of the plug and you will see a tab on the inner edge of the connector which keeps the pin in place.

Push this tab back gently and pull the wire out with the pin attached.

Insulate the pin with PVC tape or heat shrink tube.  Don’t leave it bare as it’s a +12 feed from the GUAGE fuse.

Dip-Dim Pin Removal (250 x 176)

Once you have removed and insulated this pin, plug it back into the module and test the system, what you should find is the following now happens.

With the ignition switched ON & light switch moving from OFF position:

  • Off - Everything off - Dah!
  • Position 1 - No Operation.
  • Position 2 - Side lights ONLY come on - front fogs can also be operated with side lights (UK).
  • Position 3 - Headlights pop up and come on as well as sides and fogs - if switched on.

Turning the ignition off should switch off the headlights leaving them raised and side lights on.

light switch

From position 3 to OFF the following should happen:

  • Position 3 - headlights raised ( Lit with ignition on)
  • Position 2 - Headlights turn off raised, leaving side lights on. (fogs too if switched on + ignition)
  • Position 1 - All lights turn off leaving lights raised - cleaning mode.
  • Off - Lights lower.

So if all goes well you should now have disabled your Dip-Dim system giving you complete control of your car lights and stopping the headlights raising with the side lights switched on, as soon as you turn on the ignition.

Before you refit the trim I’d recommend you check all your electric bits work correctly, just incase you missed a connector fiddling about!

A BIG thanks goes to Mavs for letting me pull apart his car to suss out this mod, cheers Mr =]

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