Thanks again for you replies.
In tests number two and three, I did attach voltmeter ground lead to the battery negative post and use positive lead to check voltage at, both leads on the bulb plug as well as both sides of the fuse, there are no voltage. I guess I have an open circuit one this side of the bulb plug.
I do not think I have bad ground as I attached voltmeter on battery positive post and checked
voltage at both leads on the bulb plugs (test no.1 ), both read at 12 volts ( it means the ground is okay, does it not?).
Now the next step is to track down the open circuit, is it not it? It is not the fuse since both sides of the fuse read 0 volts.
Next is the DIM relay. In my car, there is only one DIM relay for both high and low beams. Low beams work so DIM Relay is okay, I guess.
I might be the combination switch which is faulty so I thought I could test the continuity of the switch, but do not know which pins are used for high beams on my model.
What steps do you advise me to take? Appreciate your time.
Monday, April 16th, 2018 AT 7:58 AM