Lower headlight problem

Did you check the bulbs?
You don't replace components just because someone said it is possible that component is bad. Testings would be required to find the cause.

Yes, I replace the bulbs, the dimmer switch. check fuels also.

You did not even perform any testings and resorted to replacing components which is usually costly and wasteful.

Did you test for battery voltage to the bulbs?
Did you test the low beam headlight relay?
Are you getting battery voltage to the light switch for the low beam terminal?
Is vehicle equipped Daytime Running Lights and/or Auto Light?

Where is the low headlight relay located? Yes the vehicle does have Daytime Running Lights and Auto Lights. We check the voltage to the light switch to the low beam terminal. I have not tried replacing the ECU yet.

I have the schematic and component location description in the diagrams below. Print them out and go through them.

Try swapping the low and high relay.
Do you have battery voltage at the light switch for the low beams? If yes, most probably the low beam relay or its circuit is bad.