12V Car LED Replacement: Placement & Voltage for 600-Ohm Resistor in 2.8-3.7V Diodes Circuit

Hi,
I replaced the bulbs in the car's installation with LEDs. The diodes have a voltage of 3V (2.8-3.7V according to the datasheet) and consume 20mA, in a fired installation it is ~ 15V (14.4-14.6V), so I found out that the resistor should give ~ 600 Ohm. The closest higher ones were probably 619 Ohm and I gave them. The diodes are lit, but I measured the voltage with a multimeter both before the diode and after the resistor (I gave the resistor after the diode). There is 12V before the LED and 7V after the resistor.

Is this the way it should be? Because I think it should be ~ 3V, possibly even less because the engine is off, so the installation is 12V, not 15V.

And another question that we argue about in the robot - should the resistor be put in front of the diode, or it does not matter?

m.biruta wrote:

The diodes are 3V (2.8-3.7V according to the datasheet)

You write "diodes" - did you accidentally connect two diodes and a resistor in series?

m.biruta wrote:

should the resistor be placed in front of the diode, does not it matter?

Serial connection, so it doesn't really matter what comes first.

398216 Usunięty wrote:

You write "diodes" - did you accidentally connect two diodes and a resistor in series?

I am writing LEDs because some of these light sources are sitting in the board illumination However, I connected one diode to one terminal after the bulb.

398216 Usunięty wrote:

Serial connection, so it doesn't really matter what comes first.

As I thought. Thanks!

m.biruta wrote:

However, I connected one diode to one terminal after the bulb.

I understand that you gave a resistor to each diode? Measure the voltage on the diode itself - on its pins. (I don't quite know how you measured)