Dim Headlight

[Charles \Stretch\ Ledford]

Greetings all.

I have a 1997 Outback. The other night I noticed that the right
headlight was very dim... barely glowing at all.

I replaced the bulb, but the new bulb is just as dim as the old one.

Any ideas what the problem might be? And advice on how to fix it myself?

THANKS! : )

 

[Bill Pelka]

Check the ground for that lamp. Happened to me on a Toy Pick-up once...
Bill

 

[Edward Hayes]

Start by cleaning all the ground connections to that light. Eddie

 

[Charles \Stretch\ Ledford]

Start by cleaning all the ground connections to that light. Eddie

Hmmm...the ground, the ground... um... I reckon that's one of the three
wires that connects to the bulb, right? Any idea which one, and where
it should be grounded?

 

[Charles \Stretch\ Ledford]

Check the ground for that lamp. Happened to me on a Toy Pick-up once...
Bill

Hmmm...the ground, the ground... um... I reckon that's one of the three
wires that connects to the bulb, right? Any idea which one, and where
it should be grounded?

 

[Ned Pike]

Hmmm...the ground, the ground... um... I reckon that's one of the three
wires that connects to the bulb, right? Any idea which one, and where
it should be grounded?

To complicate things even further, Subaru headlights run on a
switched-ground format. Looking at your headlight connector the power flows
in through the center wire/pin, through both filaments, and out the two side
wires/pins. The relays deep in the dash then switch one filament or the
other to ground, thus creating the circuit. So, assuming a new bulb didn't
fix things, there isn't really anything you as an average Joe can do to fix
this. My guess is a flaky relay in the ground-switching system. IOW, it's
dealer time.

 

[Dan Duncan]

Hmmm...the ground, the ground... um... I reckon that's one of the three
wires that connects to the bulb, right? Any idea which one, and where
it should be grounded?

Why not clean them all then?

-DanD

 

[donald rarer]

check the fuses

 

[Charles \Stretch\ Ledford]

To complicate things even further, Subaru headlights run on a
switched-ground format. Looking at your headlight connector the power flows
in through the center wire/pin, through both filaments, and out the two side
wires/pins. The relays deep in the dash then switch one filament or the
other to ground, thus creating the circuit. So, assuming a new bulb didn't
fix things, there isn't really anything you as an average Joe can do to fix
this. My guess is a flaky relay in the ground-switching system. IOW, it's
dealer time.

Thanks, Ned.

Just out of curiosity, why would they use something like this? Isn't it
just as well to use a single ground?

 

[brentlz]

This is not totally bizzare, I've seen the same headlight wiring on some
older Datsun's (PL-510's in particular).

What is really odd is the way FHI chose to wire the dash lighting:
Basically, the "ground" is a constant +12V and the "hot" varies through
0V, +3V, +6V, +9V, and +12V, effectively giving 12V, 9V, 6V, 3V, 0V to
the gauge lights, which progressively dims the dash lighting. Makes it
real tough to get aftermarket gauges that share a common ground between
the sending unit & gauge lighting to work properly... As to why they
did it this way, who knows?

Brent.