Need help with headlight problem....please

[akjruthies]

Hi All,

 

I have a 1997 Legacy Outback. My passenger side headlight started fading last week, so I bought a new one (did not touch the bulb while installing) and thought that would be the end of the problem. The new headlight was very dim as well and the "brights indicator" on my dash was showing that my brights were on but, they were not. My driver side fog lamp is also out. Then I noticed that the bulb socket for the headlight was sort of fried, so I bought a new socket and replaced the old socket with the new. But, that did not remedy the problem either. Any ideas?

[OB99W]

Do they use much salt on the roads in your area? Often when there are electrical problems such as you're describing, a corroded ground connection is the cause. As an example, see:

http://endwrench.com/images/pdfs/GroundsInfo.pdf

[nipper]

i vote for bad grounds too

 

nipper

[jmondl]

I have a 2002 Subaru Outback with the same problem. I have tried isolating the problem, but have only been able to conclude that there is a short somewhere on the passenger side on the main headlight wiring. The bright light works when I jump the low beam wires from the driver side, but otherwise the high beams and the high beam indicator on the dash board malfunction. Shorts are a pain in the neck.

[OB99W]

I have a 2002 Subaru Outback with the same problem. I have tried isolating the problem, but have only been able to conclude that there is a short somewhere on the passenger side on the main headlight wiring. The bright light works when I jump the low beam wires from the driver side, but otherwise the high beams and the high beam indicator on the dash board malfunction. Shorts are a pain in the neck.

Short-circuits ("shorts") can be a pain to find. However, let's not confuse a "short" with an "open". A "short" is a connection that occurs where one was not intended. Shorts to ground of sufficiently low resistance will typically cause a fuse to blow, circuit breaker to trip, or fusible link to melt (or a conductor to overheat if there's no protective device inline) due to excessive current being drawn.

 

On the other hand, an "open" is when an intended connection doesn't occur. Since with an "open" power isn't delivered to the load, less current than normal is drawn. Some opens are as simple as a loose/corroded/blown fuse. (Don't be confused by the fact that "shorts" can cause "open" fuses :-\ .)

 

My '99 OB has separate fuses for the left and right headlamps, and I suspect the 2002 does as well. Sometimes those fuses can blow when a headlamp filament fails, since a piece of it can land across the conductors and momentarily draw high current. So, you might want to check the fuses. If one is blown, and blows again after replacement, then there may indeed be a short.

 

By the way, bad ground connections would be considered "opens".

[Distance Commuter]

Short-circuits ("shorts") can be a pain to find. However, let's not confuse a "short" with an "open"...

 

Very well put. I couldn't have said it as well myself.

[ferret]

Check your fuses. This is the symptom when a fuse is blown. Subaru provides 12V thru a seperate fuse to the "common'" point of each light element. Then they ground either the low or high to turn on that element.

 

When the fuse for instance, for the passenger light is open and you have the LOW beam on. The 12V for the drivers side goes thru the LOW beam element to ground and that side lights. HOWEVER, there is also 12V going thru the High beam element to a common point on the HIGH/LOW dimmer switch. From there it travels thru the High beam element of the passenger side, thru the common point (not at 12V since the fuse is blown) thru the low beam to ground. Hence the passenger side appears on dim. The HIGH beam indicator is also across the passenger side High beam element wiring, so it is ALWAYS lit. sometimes a little brighter than others.

 

Common problem in Subaru's since they apply power to their headlights in this manner.

[jmondl]

It was the fuse. Since the high beams came on dim, and the high beam indicator malfunctioned, I sure figured a couple of wires were shorted. Simple solution, although I'll scratch my head over the wiring plan for the car for a while.