[jonesboro]

My 2009 Corolla S is having a headlight/fog light problem.

Following are the symptoms.

Low Beams Switched On plus Fog Lights Not Switched On:
Driver side low beam bulb on "dim orangish", something wrong
Passenger side low beam bulb works properly
Both fog lights on "dim orangish", something wrong

Low Beams Switched On plus Fog Lights Switched On:
Driver side low beam does not work
Driver side fog light does not work
Passenger side low beam bulb works properly
Passenger side fog light bulb works properly

High Beams Switched On:
Driver side: high beam bulb works properly, low beam bulb on "dim orangish"
Passenger side: high beam bulb and low beam bulb both working properly
Both fog lights on "dim orangish", something wrong

Any suggestions as to what the problem might be and/or steps to diagnose?

 

[sinnaever]

Have you recently done any Mods to the electrical system in your car?

Have you changed the bulbs recently?

How long have you owned the car?

Have you recently replaced the Battery?

Best steps for diagnosis... is to take a voltmeter and see what kind of voltage you are getting from the harness that plugs into the bulbs. If you have lower voltage on your DRV Side compared to your PSG Side low-beam then there is something wrong with your electrical (harness, fuse...etc) If the voltage is the same between the two, then it could be a bulb problem.

Answer some of those questions and it will help myself and other members narrow down the root cause.

 

[jonesboro]

To member sinnaever and others,

Thanks for your response, here's some additional information on my car:

I just purchased this vehicle used with 18,000 miles on it.

The previous owner claims he never did any mods to the vehicle, I believe him since there are no signs of any mods.

To my knowledge the bulbs have never been changed and the battery is the original.

The vehicle has never been in a wreck or had major repairs.

 

[jonesboro]

Latest on my Lights Problem

I tested the voltage going to the low beam bulb on the driver's side and got 12+ volts, the same as when I tested the passenger's side. The low beam on the passenger's side works fine so I switched the low beam bulb from the passenger side to the driver's side. Good bulb placed on the driver's side is now dim "organish" on low beam. The problem is clearly not the bulb.

I'm wondering if this could be a relay problem. When I turn on my low beams the fog lights both come on a dim "organish" even though the fog light switch is in the off position. I've heard there is one or more relays in the fog light circuit that allows the fog lights to turn on only when the tail lights and low beams are on.

I suspect this relay must be in the fuse box under the hood but if so, exactly where in the fuse box is this relay, or if not there where is it?

Any other ideas on what I should be testing/looking for?

 

[jonesboro]

Here's some more information.

Using my voltmeter to check the low beam circuits:

LOW BEAMS ONLY ON

On the wires going to and from the passenger's side low beam bulb I read 12.6 volts on the positive side and 0 volts on the common side.

On the wires going to and from the driver's side low beam bulb I read 12.6 volts on the positive side and .4 volts on the common side (shouldn't this be 0 volts?).

LOW BEAMS ON PLUS FOG LIGHTS ON

On the wires going to and from the passenger's side low beam bulb I read 11.8 volts on the positive side and 0 volts on the common side.

On the wires going to and from the driver's side low beam bulb I read 11.8 volts on the positive side and 11.8 volts on the common side (shouldn't this be 0 volts?).

It appears that there's something strange with the common side circuit coming from my driver's side low beam bulb. Any ideas on what could be causing this? Is the fog light relay still a suspect?