The computer has a setting that can be changed for LED lights. Take your Volvo to the Volvo dealer and have a tech readjust the threshold for the lights you have replaced and have that done for those you are going to replace. EACH light has to be done separately because of the way Volvo and Mack for that matter are setup.
Each light is setup through the body computer to sense a failed (burned out) light and this is done by measuring the current on each light when the power is applied. The little current sensor gives the computer a voltage level and if the voltage is low, it tells the Dash Computer that the lights out and tell the driver.
As mentioned, the LED light presents little in the way of a load on the circuit, hence it looks like it is burned out. The old buld has something like 220 ohms of resistance that produces a load when power is applied, the LED has something like a million ohms so there is in effect no load.
DO NOT wire a resistor in line with anything, it will cause more problems for you in the long run and when you go get your truck repaired, they will rip all of them out and replace the LEDs with IC bulbs.
