@Santa Fe Joe posted:See the wires running up to the top corners? The wires run from circuit board to the upper corners
You are likely best to take out that circuit board and actually identify the components- specifically the regulator.
Typical circuit for 78XX voltage regulator from AC incoming power on the left. RL is the load. This circuit in the car appears to not have any capacitors for DC smoothing.
That voltage determines the resistor value when using LEDs
Also, we need an understanding of if that board has resistors or other current limiting in series with the LEDS- otherwise, you need to put them in series with the the LEDs
LEDs have a forward voltage before they conduct- that is NOT the same thing you are asking, AND, they need EXTERNAL current limiting (AKA a resistor in series or some other control for current).
LED- acronym- Light Emitting Diode- so it's a diode. Once it begins conducting- that basically is full tilt what the power source can provide.
https://www.digikey.com/en/res...-led-series-resistor
