I just joined this group. Looks like a good one.

 

I recently bought an 01 OB wagon H6 with 72,000 miles. It seems in good condition, but has one strange attribute. One of my lowbeam/daylight headlights will go on or off randomly. Sometimes one light will be on and the other off. Then they might switch. Or, both may be off for a while. Or, both on. There seems to be no pattern to it and no predictability. Sometimes a bulb will burn out, but usually they just stop working for a while. I've checked the connectors to see that they're well seated. I've also checked the voltage on each lead (I was surprised it was not +12v and 0v, but have no reference to tell me what it should be).

 

Has anyone else had to deal with this? My wife asked the dealer about it and they said, "That's interesting. We've never had that problem before." To me, that translates into a lengthy search, which spells $$$$$.

 

I suspect it might be a poor ground, but have no idea where to look for that. Any ideas?

 

Thanks,

Dale

I just joined this group. Looks like a good one.

 

I recently bought an 01 OB wagon H6 with 72,000 miles. It seems in good condition, but has one strange attribute. One of my lowbeam/daylight headlights will go on or off randomly. Sometimes one light will be on and the other off. Then they might switch. Or, both may be off for a while. Or, both on. There seems to be no pattern to it and no predictability. Sometimes a bulb will burn out, but usually they just stop working for a while. I've checked the connectors to see that they're well seated. I've also checked the voltage on each lead (I was surprised it was not +12v and 0v, but have no reference to tell me what it should be).

 

Has anyone else had to deal with this? My wife asked the dealer about it and they said, "That's interesting. We've never had that problem before." To me, that translates into a lengthy search, which spells $$$$$.

 

I suspect it might be a poor ground, but have no idea where to look for that. Any ideas?

 

Thanks,

Dale

it would be interesting to know if when you put them on high beam if they stay on?

it would be interesting to know if when you put them on high beam if they stay on?

 

I'll check it tomorrow to confirm, but I don't believe that is an issue. I believe they go off when the high beams go on.

 

Also, high beams work fine. They do not have the problem. My wife did report once that the fog lights did the same thing, although I have not seen it.

 

Dale

check the head light relays, and the plug at the headlight. May need a new pigtail due to corrosion.

 

 

nipper

You should have 12v going to terminal 2 of the lights all the time, from the fuses. The low beams (They are tied together) are actuated by a ground on terminal 1, either from the daytime light resistor or the light switch. Either way, they both make contact in the daytime light relay.

 

It doesn't make a diff if the lights switch is turned on?

 

I don't know why it is switching between lights, but that being the case, maybe it's the point where the low beams tie together, which on my diagarm is on the yel/blu wire on the left light. I'm not sure if there is a connector, or a splice.

Just seen this thread after posting the same problem with my 02' Legacy GT.

Have you ever figured it out?

 

-Michael

I would suspect the problem is either with the headlight relays or the in the Daytime Running Light Control Module which controls the ground to the lights. There may be a problem with the left and right relays that tie power to the lights. Fuses 8 and 9 in the main fuse box under the hood supply power to the left and right headlights. When you have the problem again I would check power at the fuses while trouble is happening. As with most all voltage measurements, you reference the voltmeter common lead to a good ground point on the car. If you have 12 volts at the fuses then I would suspect the DRLM module next. If you don't have 12 volts then you need to check that headlight relay for a problem which is also in the M/B box.

Thanks for the pointers,

what is M/B vox and where does it live?

Where could I get a wiring diagram and some reference explaining where the different electricals are found in the car?

 

-Michael

I had a problem with our 95 Legacy, headlight out, replaced the bulb, 2 weeks later same thing, replaced bulb and nothing. The socket the bulb was plugged into crumbled (from heat?) Spliced in new socket and no problem. The socket wasnt obvious the first time. My 2 cents!

Thanks for the pointers,

what is M/B vox and where does it live?

Where could I get a wiring diagram and some reference explaining where the different electricals are found in the car?

 

-Michael

 

The M/B box or main fuse/relay panel is Subaru's name for the power distribution box in the engine compartment. The F/B panel is the fuse panel in the dash.

 

Roger1 makes a good suggestion for the possible cause of this problem.

I had a problem with our 95 Legacy, headlight out, replaced the bulb, 2 weeks later same thing, replaced bulb and nothing. The socket the bulb was plugged into crumbled (from heat?) Spliced in new socket and no problem. The socket wasnt obvious the first time. My 2 cents!

 

The bulbs on my `02 don't go into the socket, they are held by a clip in place. and two wires just plug on the bulb pins.

 

 

-Michael

Just did some troubleshooting following your leads,:

checked both LH and RH headlight fuses and relays in the M/B - everything looks nice and clean,

started the car - problem is there: left headlight is on, right headlight is off,

measured voltage on the RH fuse - 14V,

pulled RH relay, voltages on the relay contacts all read - 14V except one, which I suspect controls the thing.

pulled LH relay - left headlight went out, but the high beam bulb came up, athough very dim,

plugged the LH relay back, and both right and left headlights are now up, and bright.

Turn the car on/off few times - all up.

It is all looking good now, but WTF? Why was it happening? Why pulling out and plugging back the Left headlight relay fixed the Right side?

I suspect, there must be some brain, that goes nuts - is it DRL control module? Where is it? Where is the light sensor located, may be it is just dirty, and it cannot decide whether it is night or day?

 

Is this system designed in the way, that when the low-beam bulb goes out, it gets the hi-beam to help? Smart :-)

 

Thanks for all the help and advice.

-Michael

The simple act of removing and reinstalling an electrical connection can clean off any corrision that is giving you electrcial issues. You cant always see the corrosion.

 

nipper

The simple act of removing and reinstalling an electrical connection can clean off any corrision that is giving you electrcial issues. You cant always see the corrosion.

 

nipper

 

Agreed, but it was removing the left headlight relay, that actually "fixed" the right headlight, not the right headlight relay....???

 

-Michael

I assume your car uses the 4 headlight system which is a little different than the 2 light system.

 

Since you had 12 volts at the fuses while the problem was occuring that means your power and relays are ok. When you pulled the left relay and saw the high beam on dimmly I think you were seeing some power backfeeding through the highbeam lighting system which may be normal due to the circuit design. The problem you are having would seem to be due to a faulty ground pin to the lights which is pin 2(yellow/blue wire) of the socket.

 

I now don't think that the DRLCM module is at fault since my drawing shows that the ground for both low beams is commoned together. The only way I can see that either or both lights can be off is due to the socket connection. From what I can see in the manual, the DRLCM module is below the radio in the center console. There are 2 connectors going to it. One is a 8 pin and the other is a 10 pin. The 8 pin connector is black and the other may be white.