Convert the Interior light to work with LED

The interior light of my Hilux has always given me problem since the day I bought the Hilux. The globe frequently looses contact and then the light stopped working. Besides it only working whenever it felt like it, when it worked it was also not very bright.

Here is my R13.00 solution:

I bought 4 x 5mm bright white LEDs from an electronics shop in Cape Town at R3.20 each

I removed the interior light from the vehicle.

I drilled 4x 5mm holes in the cover. I drilled the holes a bit skew in order to focus the LED more or less to where each passenger will be sitting. The LED emits the most light in the centre of the LED.

Remember that LEDs must be connected the right way around otherwise it will not work. ie. + must be on the + side.

If you look at the LED you will see that it has one long leg and one short leg. Also if you look at the casing you will see that there is a flat side. The short leg and the flat side are both on the Negative side of the LED (cathode). The long leg is the Positive (anode) . If you look at the plates on the inside of the LED you will see that the positive side is normally the small plate and the negative is the bigger one. Thus there are three ways to determine which leg is which.

Negative - = Short leg on flat side, with big cathode on inside.
Positive + = Long leg on round side and small anode on inside

A LED is rather sensitive for the voltage it operates at. White LEDs normally function at about 3.4 Volt. Normal red and green LEDs normally operates at about 1.8 Volt.

For this mod I used white LEDs. So I reckoned that if I put 4x white LEDs in series I will need 13.6 volt for them to work effectively. 3 LEDs would need only 10.2 volt. I opted for 4 LEDs because 3 LEDs in series might get damaged especially if the engine is running and charging at 14 Volts.

To connect the LEDs in series you need to connect one positive leg of a LED with the negative leg of the next.

I did not use wires to connect the LED, I just sommer used the LEDs' own legs for it. In the pic below you will see that the legs on the long side do not overlap much, when you drill the holes keep the length of the legs in mind, I did not and it almost worked against me.

I attached two wires to the contact points of the unit. Note that the positive side is the one closest to the switch. In the pic below you can see I first tried to solder it onto the tracks, it did not work, connect it directly to the contact points.

Then connect the wires to the LEDs and make sure you connect + to +

Put it back and you have a R13.00 worth of converted LED interior light for your Hilux. If it is not bright enough for you, you can install another cluster of 4 LEDs connected in series and connect that in parallel to the first cluster. To connect it in parallel you should connect the + of the one cluster with the + of the other cluster, etc.