Low beams hight beams do not work on my left side please help me

Voltage regulator inside the alternator is probably stuck closed. It is unlikely that the low beams not working is connected to that problem. mostly the low beam bulds are burnt out or something is wrong with the wiring or the dimmer switch.

both LOW BEAMS (you make this so hard not saying that...)
but challenging.....

is car in canada, or usa? or a?
does car have DRL. we dont know ,until you say.
and both types work different, non- and DRL.
my answer (roll dice, ) USA. no DRL

the system is simple (alldata.com)
2 fues, left and right
2 relays, one left, one right.
1 controller box.
1 switch combo.

the sequence of events
HL switch on,
this ground the Low pin on the mutiplex control box in fuse box.
this box sends 2 ground signals to both relays.
so if one headlight works you know the mpx box works
both relays close
and 12v is sent to both low beams , and there other side is grounded full time so they glow.
there are 2 fuse left and right. fuse #15 and 17

you need a new light bulb. there are two different bulbs for high and low beam or 2 filements in one bulb. ether way you need a new light bulb

the low beam element has burned out in the light bulb itself - buy and install a new bulb,, this will fix your problem. ( your local auto parts store will carry the replacement bulb ).

c...

12 METERS THE LOW BEEN SHOULD BE THE HIGHT OF A BUMPER , CONCENTRATED LIGHT SHOULD BE STRAIGHT ON THE LEFT SIDE AND THE RIGHT SIDE A LITTLE BIT TURNING TO THE RIGHT.

Power for the headlights on the Left side (High and low beam.) comes from the same fuse... The ORANGE wire and the ORANGE/BLACK are the same, they connect in the harness. If you only lack the 12v to make the light work connect them at the headlight assembly.

If your low beam also lacks ground the Left low beam ground is shared with the right low beam ground... Run a wire from left low beam DARK BLUE to right low beam DARK BLUE/WHITE.

If its not working now then your cursed, seek a witch doctor.

You need to get a volt meter at the headlamp plug (Wiring harness) to see if you got a ground, power from the low beam wire, and then power from the hight beam wire. It's the best place to start.

Bad lamps? bad connection to lamp? I know already checked :( right?

THE LOW BEAM HALF OF THE BULB HAS BURNED OUT AND NEEDS TO BE REPLACED. HOPE THIS HELPS. LET ME KNOW PLEASE. THANKS FOR USING FIX-YA.

Your headlamps [lowbeams] work with the alarm system under the passenger seat. Any malfunction with the alarm devices under the seat will interfere with your headlights [lowbeams] functioning . I used to have the same problem with mine until I changed my alarm devices. I will advice you to go to a junckyard near you and remove the passenger seat from an 84-89 300zx and with a 14mm socket remove the seat,then; used a 10mm socket to remove the alarm devices. Do not worry, the wirings are the same on all of them. Good luck!