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Discussion Starter #1
My 05 Outback suddenly started having no headlights on, switch off or on, but if the e-brake handle is up or the shift lever in in R, the driving lights (no highbeam function) are on. This is the exact reversal of the normal situation, which is driving lights on when headlight switch is off, but they go off when the e-brake is lifted (but DO NOT go off when the car is in R) The backup lights do not work, and the fuse (#18) is blown, so I suspect this has something to do with a short in the rear hatch wiring harness? (I have already have that tee shirt from another 05 Outback that we also own). Anybody got any ideas where this problem arises from?
 

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You answered your own question! If you suspect an issue with the hatch wiring, then that needs to be checked and corrected first!
Mechanics 101..... Fix the know problems first before you make it any harder than it needs to be!
 

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Discussion Starter #3
Well, I just looked, and sure enough there were 5 or so bare wires visible inside the hatch wiring boot, so I covered those with electric tape (huge pain), replace the fuse, and as soon as I energized the system, the fuse blew again, and the same weird headlight issue is going on (and no back-up lights). I guess I'll try replacing the entire wiring harness (since it obviously needs replacing, $110 and lots of fiddly screwing with interior panels), and see if that fixes the headlight problem.
 

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Just to be sure, automatic or manual transmission?

Broken backup light wires to the rear hatch can blow that fuse. But if the car is a manual, the back up light switch is located on the side of the transmission and there's been cases of the wires at the switch, or the switch, shorting, causing the fuse to blow.

There's a good number of posts related to fuse #18. A search here should provide good info.
 

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Discussion Starter #5
It’s an automatic. Sort of suspicious that the driving lights come on when the car is put into R. I covered all the obvious bare wires in the hatch boot, but it’s so hard to really see everything in there that I could have missed one. I remember you asking about what color wire from an earlier related post, the five obvious bare wires were purple, all black, light blue, brown w/yellow, and black/silver. The photo would have looked almost the same on both of my 05 outbacks. I was a bit disappointed but not surprised when isolating the obvious shorts in the hatch boot changed nothing and the backup light fuse immediately blew.
 

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It’s an automatic.
Okay, 05, Outback, automatic. Let's add, is it a H4 2.5, H4 turbo, or 6-cylinder? (There are some wiring differences in the backup light circuit.)

and the backup light fuse immediately blew.
Did the fuse blow when the gear lever was moved to or through Reverse, or was it in another gear (not R) when that happened? Also, just to confirm, does this happen only when the ignition switch is at On, and not when it's at ACC or Off.

Also, was the rear hatch open or closed at that time, and does this make any difference?

Sort of suspicious that the driving lights come on when the car is put into R.
Your symptoms, including this one, have been reported in other threads related to a blown fuse #18.

Could you clarify what is meant by "driving lights"?

The absence of headlights is because the Daylight Running Lights control module is also powered by fuse #18. The DRL module controls (switches on and off) the headlights. When the fuse is blown, the DRL module is disabled and won't turn on any headlights, DRL or low beam. (The fog lights are also involved, and don't work when the fuse is blown.) However, I have not yet been able to figure out why the DRL lights seem to come on if Reverse is selected.

the five obvious bare wires were purple, all black, light blue, brown w/yellow, and black/silver.
The back-up light circuit in the hatch uses brown w/yellow stripe, so that might be the one. But apparently there's still a short, so the wire could be exposed/grounded elsewhere in that area.

Have a multimeter? Remove fuse #18, have the gear selector in P, parking brake applied, and the ignition switch Off (key out). Remove the two backup light bulbs from their sockets.

One of the two fuse #18 contacts in the fuse panel has 12 V all the time. The other should have no voltage. Measure at the two contacts (to ground) to identify them. Then, measure the resistance between the contact with no power and ground. If it doesn't show a short, turn the ignition switch On, move the gear selector to R, turn the ignition switch back to ACC (it won't go all the way to Off), and again measure the resistance between the fuse #18 contact with no power and ground. Presumably it will confirm the short.

Alternatively, the wiring harness that comes into the car from the hatch goes down the right rear pillar to two or three connectors. (See red circle in attached photo.) When the trim piece on the pillar is removed, the connectors might be exposed, otherwise the right side lower trim panel of the cargo area has to be moved out. If the connectors are disconnected, that takes the hatch harness completely out, including the area of the flexible boot, in which case the fuse should not blow.
 

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Discussion Starter #7
Thanks very much for the info. So, the engine is the regular H4 2.5, automatic. I foolishly did not bother to isolate any various conditions after I put the new fuse in (in my hubris thinking I had solved the problem by insulating the exposed wires inside the hatch boot), all I did was replace the fuse, start the car, and then immediately notice that the headlights did not work, switch off (what I call driving lights, they are on whenever the car is running unless the e-brake is up) or switch on. Also, same symptoms of lights (driving only, no high beam function) come on with e-brake up AND if car is in reverse. I am about to replace the rear wiring harness in my other 05 outback, and looks like I will probably have to do the same in the one with the headlight issue, but I will definitely conduct the diagnostic you recommend to see what I can learn.
 

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all I did was replace the fuse, start the car, and then immediately notice that the headlights did not work,
If the engine was just started, I would think the transmission would have to be in P or N. That being the case, if there's a short in the backup light circuit, the fuse wouldn't blow until the gear lever is moved to, or through Reverse (e.g., as when moving from P to N and D). IF the fuse blew with the transmission in P or N, then the short that's blowing the fuse might not be in the backup light circuit! Transmission gear selector position might seem to be unimportant, but in this case it's a key factor.
 

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Discussion Starter #9
Well, I did put it into R, but that was after I already saw that the headlights weren’t coming on.

Anyway, I did some more digging into the hatch wiring boot, and found more bare wires I had missed, covered them with electric tape, replaced the backup light fuse (#18), and first checked the fuse without energizing anything (not blown), then with the car started but lights off and not shifted to R, and then lo and behold, lights worked as normal and backup lights worked as normal too. So I’m going to replace hatch wiring harness ($110 from dealer and lots of trim removal) since I suspect the problem will resurface since all those wires are so rotten in the hatch boot.
 

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I did some more digging into the hatch wiring boot, and found more bare wires I had missed,
Great. (The backup light wire was probably exposed/broken in more than one place?)

I noticed in your boot photo that a part of the boot grommet (red circled in this photo)

boot.jpeg

is separated from the harness that's hidden down beyond the hole in the car body. That "tab" extends down along the wire bundle and is held against it by the tape wrap (at least that's the way it is on my 07.)

471213


On first thought, the tabs don't seem to have an obvious purpose. I've wondered if the tab might be intended to relieve strain on the wire bundle. My thought is that if the tab breaks or separates from the bundle, the wires at or just below the hole might be under more tension, and more prone to flex at one point as the door is opened and closed, leading to the breaks. In other words, the separated tab could be the precursor to the wires failing.

Hope you will follow up on the replacement of the harnesses . . .
 

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Well, I did put it into R, but that was after I already saw that the headlights weren’t coming on.

Anyway, I did some more digging into the hatch wiring boot, and found more bare wires I had missed, covered them with electric tape, replaced the backup light fuse (#18), and first checked the fuse without energizing anything (not blown), then with the car started but lights off and not shifted to R, and then lo and behold, lights worked as normal and backup lights worked as normal too. So I’m going to replace hatch wiring harness ($110 from dealer and lots of trim removal) since I suspect the problem will resurface since all those wires are so rotten in the hatch boot.
I think I stated back up in post #2, the first response to your thread, that you needed to fix the known problem first before running around in circles! I guess you cost yourself some extra time, some speculation by others, and you are know behind by 3 days on ordering the part!

BTW..... if you shop around the part can be had for about $75.00!
 

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Well, I did put it into R, but that was after I already saw that the headlights weren’t coming on.

Anyway, I did some more digging into the hatch wiring boot, and found more bare wires I had missed, covered them with electric tape, replaced the backup light fuse (#18), and first checked the fuse without energizing anything (not blown), then with the car started but lights off and not shifted to R, and then lo and behold, lights worked as normal and backup lights worked as normal too. So I’m going to replace hatch wiring harness ($110 from dealer and lots of trim removal) since I suspect the problem will resurface since all those wires are so rotten in the hatch boot.
You can successfully run the "updated" harness (the "B" version) which is under $100, looking around online. The "A" harness is NOT cheap (and is the majority of 2005 OBs).
 
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