Please help! Headlights turn off when High beams are activated

[Cliff]

For a '95 Subaru Legacy 2.2L SOHC

If anyone has a wiring schematic it would be a big help to me. I get
no voltage in the high beam wire (measured at the headlight) and the
impedence in the ground wire changes from like 40 ohms to zero
continuity when I turn on the high beams, hence the lights go out. If
anyone has a wire diagram for the headlight switch I could really use
it. Thanks!

Cliff

p.s. feel free to email me. just take the "nospam||" out of the
address

 

[Edward Hayes]

Check fuses

 

[mulder]

For a '95 Subaru Legacy 2.2L SOHC

If anyone has a wiring schematic it would be a big help to me. I get
no voltage in the high beam wire (measured at the headlight) and the
impedence in the ground wire changes from like 40 ohms to zero
continuity when I turn on the high beams, hence the lights go out. If
anyone has a wire diagram for the headlight switch I could really use
it. Thanks!

Cliff

p.s. feel free to email me. just take the "nospam||" out of the
address

The headlights are a common positive, switched ground system. You
won't see voltage on the "high beam wire" when the high beams are on
because it is being switched to ground. So there is nothing wrong with
the readings you are getting. If I'm not mistaken you have
dual-filament bulbs, probably H4. I'm willing to bet that the problem
is both low beam filaments have burned out. Check the bulbs visually
and with an ohmeter, and try new bulbs.

 

[AS]

40 ohms is too much, check the ground connections. Besides, I would not
use my meter to measure impedance when there is current flowing in the
circuit, measure voltage or amps.

I hope you already checked the fuses before posting here.

Via email you will get the diagrams. In the mean time, in the vehicle
with no DRL, the light switch controls the ground, not the positive,
which comes from fuse 26 for the high beams or fuse 24 for the low beams.

Good luck

AS

 

[Cliff]

how is it being switched to ground if the lightbulbs are disconnected?
I'm checking the voltage at the connectors with both disconnected from
the bulbs

 

[mulder]

how is it being switched to ground if the lightbulbs are disconnected?
I'm checking the voltage at the connectors with both disconnected from
the bulbs

The ground switching is done through the headlight switch. There are
three terminals on the connector- one is the common positive that is
switched on/off by the headlight switch, and will have power when the
key is on and the headlights are turned on. The other two are switched
grounds for the low and high beams respectively.
You don't have a power problem since your high beams work, and the
power is common to both.
Most probably you are taking the long way around to finding out that
your bulbs are blown.

 

[Bill Pelka]

Check for continuity thru the bulbs. There should be 3 pins sticking out.
The bulbs I have as a spare set were the originals with my '95 LSi. They are
OSRAM HB2 DOT 9003L Germany Bilux 12v 60/55w H4 37R E1 00801 w4/2. There is
a flat spot on the front of the metal base. On the back there are 3 pins.
The center one is horizontal and the other 2 are verticle. Ohm values are as
folows: With the pins facing you , left to center is .2 ohms, right to
center is .2 ohms, left to right is .2 ohms. All pins to metal base are
infinite. This measurement is hard because of the low value and the
resistance in the meter leads. But having continuity at least tells you that
you don't have a burnt out bulb. WallyWorld has a good price on these lamps
and I have heard rumors that they burn out very close to each others
lifetime... If you have a 12 volt test lamp, instead of using ground and
looking for power with the pin tip, hook it to positive and try to find
ground...

Check out this page...
http://www.danielsternlighting.com/

Bill

 

[Cliff]

THANKS TO EVERYONE for their help and advice. With the schematic that
AS sent me, I was able to find and fix the problem. I eventually
discovered the highbeam ground (red) wire was damaged and corroded
between the bulbs and the firewall (in the wheel well). I could never
have figured it out without the schematic with its wonderful wire
harness pin diagrams.

I checked the bulb elements and they were ok, but that actually was
good advice. It probably is more likely to have both HB elements blow
a couple of days apart, than a wiring problem.

anyway, thanks to those who gave great suggestions like "check the
fuses," lol

 

[mulder]

THANKS TO EVERYONE for their help and advice. With the schematic that
AS sent me, I was able to find and fix the problem. I eventually
discovered the highbeam ground (red) wire was damaged and corroded
between the bulbs and the firewall (in the wheel well). I could never
have figured it out without the schematic with its wonderful wire
harness pin diagrams.

I checked the bulb elements and they were ok, but that actually was
good advice. It probably is more likely to have both HB elements blow
a couple of days apart, than a wiring problem.

anyway, thanks to those who gave great suggestions like "check the
fuses," lol

Good to see you found the problem. In most cases the symptom of no low
beams would in fact be from burned out bulbs. Given the age of your
car, it's understandable that it actually turned out to be corroded
wiring.

 

[Sheldon]

THANKS TO EVERYONE for their help and advice. With the schematic that
AS sent me, I was able to find and fix the problem. I eventually
discovered the highbeam ground (red) wire was damaged and corroded
between the bulbs and the firewall (in the wheel well). I could never
have figured it out without the schematic with its wonderful wire
harness pin diagrams.

I checked the bulb elements and they were ok, but that actually was
good advice. It probably is more likely to have both HB elements blow
a couple of days apart, than a wiring problem.

anyway, thanks to those who gave great suggestions like "check the
fuses," lol

Glad you found it. A friend and I spent an entire day trying to figure out
why he had no taillights. Bulbs were blown.