When i turn on my headlights the left side gets dim and the running lights all go dim but the right head light and running light are bright. the dash lights also goes out on just the head light setting. If you turn on the Parking light switch all the running lights get brighter and so does the dash lights. What should i do? Its a 1993 subaru loyale wagon 4wd

You have a check engine light on your dash

What codes have you retrieved?

Get your codes & google them

Check Ground wires to your head light harness try grounding the ground wire on lamps if they go bright U have ground problem if you ground it all lights maybe effected by this problem remmemmber only left side so sounds like ground try it

Joe

head light control module under dash driver side

There is nothign wrong with your car-when you turn on the headlights the car believes you are turnung them on because it is dark outside, so it automatically dims your dashboard lights for you (since it now thinks it's nighttime). Your car already has daytime running lights, so you don't need to turn your headlights on in the daytime-they come on automatically when the car is running. You can keep your dash lights dim or bright by adjusting the small black dial on the left side of the dashboard, whether headlights are on or off if you want to.

If the headlights were not changed at the same time the dim one may be about to go out. If you change the dim one and not both of them the other one will most likely get dim while the other is still bright

Follow the ground wire ( black to the raditor suport and reconnect it or add aground wire from it to the battery ground and it'll work good. Bet it goes out if you unplug the other headlightas it's grounding thought the other light.

Try swapping the headlight bulbs or buying a known good bulb and testing that way. Sounds like a shorted bulb filament issue.

This is a problewm I have been researching. On the 91 Loyale there are two headlight relays. The relay for the left headlight also controls the instrument lights and the running lights. If the right relay is working and the left is not, the left headlight will be dim because of a back electrical path through the high beam indicator light on the dash, but the instrument and running lights will be out. I have been trying to find out where Subaru put these relays, but three Subaru service departments have been no help. One dealer's service department told me to remove the large bezel around the instrument panel. I did and the relays weren't there. Lots of luck.
John

It's the dimmer switch in the column.

The only thing that all of your problems have in common is the light switch and the dash wiring harness. The stereo is linked to the light switch because of it's illumination feature' You need to test the light switch with a test light by probing the wires at it's plug.