Materials:    (see Scott's Shop)  Soldering and assembling the cap should take about 5 minutes, not including the warm-up of the soldering iron. 

1.  Connector for MR16 lamp,  GU5.3 Base.     All hardware stores and Conrad 2.51 Euro  have these.

2.  Female 5 mm x 2.1 mm connector:  Conrad 73948 0.84 Euro

3.  three 6-7 mm (3/32" dia) pieces of shrink tubing

4.  Switch Conrad  Conrad 700000-63   2.35 Euro

5.   50 mm End cap (HTM DN 50).   All German hardware stores carry the Marley brand.  You need the following openings in the end cap.

Click here for tips on easily cutting the square opening for the toggle switch. 

Tools: Wire cutters, soldering iron, small flat screw driver, solder, (10 or 11mm) wrench for nut on femal connector.

Cut lamp base wires to 45 mm.  From the remains, cut one piece 70 mm long.

Here shown is the lamp base with 45 mm leads and one 70 mm piece. 

After cutting strip off about 3-4 mm of insulation on each piece.

Tin the ends of the wire with solder.

Cover the ground terminal with a piece of shrink tubing.   This terminal is not used.

Tin the remaining two terminals with solder, so that soldering the wire later will be easier.    Be careful not to leave the heat on the connector for too long, or you might start to melt it.  You can "heat sink" the connector by plugging it into a male connector.   This also helps to fix it during soldering. 

Terminals after tinning. 

Solder the 70 mm piece of wire to the terminal opposite the terminal with shrink tubing.   You can insert a male connector in the female connector to help stabilize it for soldering and to act as a heat sink. 

On one wire of the lamp connector slide on a piece of shrink tubing.   Solder that end to the terminal.   

Slide a piece of shrink tubing over the first wire and soldered terminal end.    Shrink the tubing on to insulate the connections.   The finished piece should look like this. 

Assemble the female connector in the 8 mm hole.   Orient the connector with the cap as shown here.    To the left is the single wire, to the right is the lamp connector.

Loosen the screws on the switch.. 

Thread the single wire through the square hole.   Connect the wire to the switch as shown in the picture.   Use the bottom screw for the connection.   The switch will be assembled with the screws facing outwards.

Feed the other lose end through the square hole.  Slide the wire in hole and tighten down the screw.   Push the switch into the square opening in the cap.

Bend the wires so that the connector will sit between the switch and the connector.  

The cap is now ready for final assembly to the lamp.