Rear hatch won't unlock, locks fine. Motor works

[griffin.malone]

Hey! Very novice when it comes to electrical work.

So recently my rear hatch stopped locking and unlocking. Nothing worked. I got out my multimeter did some tests on the two wires going to the actuator. The Green Yellow one will unlock the hatch if I bypass the ground (other wire) to somewhere on the hatch. So I assumed the black striped one was the ground, and not working. Temporarily (before I trace the non working ground) I closed the ground off and created a floating ground in the hatch. But then I realized it will lock but still won't unlock. It unlocks fine, but when I try to unlock it the motor spins a TINY bit and that's it. Is the wire I thought was a ground power to make the motor turn the other way...? 

Ive tried to look online but can't seem to find answers. How does the actuator work? Do I have it completely wrong? thanks!!

[heartless]

year and model would be helpful.. but most likely you have broken wires in the boot that goes between the body and the hatch. this is pretty common

you can find factory service manuals here: http://jdmfsm.info/Auto/Japan/Subaru/

[lmdew]

It would help to have the year and model.  Many time the release lever handle pivot points are rusted.  A little PB blaster and working the handle a bit will free it up.

[griffin.malone]

I used some on the handle and still nothing. 2005 legacy. Sorry, forgot about that.

[Rampage]

Hope you didn't burn out the Door Lock Timer by grounding that wire.

What you call a motor is actually a solenoid. The two wires going to it are switched by the Door Lock Timer, one polarity to lock and opposite polarity to unlock. One wire hot the other wire ground to lock and the opposite to unlock. The solenoid has a center position and will either push or pull the door lock depending on the polarity used on the two wires.

Put the wires back the way you found them.

If it still clicks when you use the button to lock and unlock, try this. I found this answer here many years ago for our 95 Legacy wagon.

Open the drivers door.

Hit the button to lock all doors.

Go around to the rear hatch and push in on the handle hard.

Go back and hit the button to unlock all doors.

Now try the hatch and see if it opens.

[griffin.malone]

Thanks for the advice. still doesn't work sadly. There is no click whatsoever. Are you saying the wires switch depending on what mechanism recently went off? So one wire is a ground, then they switch? Thanks.

[Rampage]

If it is not clicking at all, as "heartless" said, check the wires in the rubber tube that goes from the hatch to the body. It will be at the top by the hinges. You have the colors of the two wires.

I'll check the FSM wiring diagram and check back.

[brus brother]

 

This is what I found on my 05 Outback.

Didn't notice broken wires until I removed some tape and started tugging on wires.There were two complete breaks.

d

Edited September 23, 2019 by brus brother

[Rampage]

Well, I really hope both wires are broken now. When you grounded one of the two wires and operated the lock unlock switch, it may have burned out one of the outputs in the "Body Integrated Unit". I don't know if it has short protection built into it or not.

In the diagram you can see the operation of the actuators. The big block is the door lock timer built into the Body Integrated Unit (aka body control unit or module). Pins 2 and 3 control the door lock actuators.

I am not sure of the polarity it uses, but here is an example. If pin 2 goes positive and 3 goes ground the doors will lock. If pin 2 goes ground and 3 goes positive the doors will unlock.

 

[griffin.malone]

Thanks for finding that page.I found someone else that's BIU was fine and they tried a similar thing I did, so hopefully it has a surge protection. Not really sure where to go from here. Best option to try to trace the wire (unlock one in this case) back through the car and hopefully it's broken somewhere? This may be past my electrical expertise... 

[griffin.malone]

I'm gonna start tracing that black/white wire farther back to check for a break tomorrow in the light. 

[brus brother]

2 hours ago, griffin.malone said:

Thanks for finding that page.I found someone else that's BIU was fine and they tried a similar thing I did, so hopefully it has a surge protection. Not really sure where to go from here. Best option to try to trace the wire (unlock one in this case) back through the car and hopefully it's broken somewhere? This may be past my electrical expertise... 

Common things occur commonly.

That flex point in the rubber boot from the body to the hatch is a very common site for the wire to fatigue.  

The first time I looked, I overlooked it but at the urging of a Subie tech, I  dove back in an tugged on each wire.

This requires NO electrical expertise.

[sirtokesalot]

re attach the wires. the other end is likely there somewhere.

[Numbchux]

Yep, '05-'09 Leg/OBK wagons were somewhat prone to the hatch wires breaking where they are bent every time the hatch is opened and closed. When I worked at the dealership, we stocked all the versions of the hatch harness (there were like 4 different part numbers. IIRC about $80, which is waaaayyy cheaper than paying hourly to fix each individual break, only to have other wires still brittle).

[Mitchy]

After a rear end shunt in the Forester I had the same problem. It was diagnosed as a bent latch.

There is a threaded latch rod which I adjusted and the tailgate locked and unlocked again by key or by central locking no problem. 

A bit of trial and error fixed this mechanical failure 

[Hellzbellz1234]

this happened on my 97 wagon and i had to replace a bunch of wires from the hatch harness

heres a super simple way to do it.

_________________________________________________________________

Tools Required:
Multimeter

Wire Stripper

Wire Coat Hanger or solid welding wire

Electrical Tape

about 30-40 feet of wire. i used red and yellow wire

lots of butt splices

__________________________________________________________________

TAKE PICTURES TAKE PICTURES TAKE PICTURES TAKE PICTURES

Pull out all of the trim near the hatch. (on 97 outbacks you have to start pulling the trim at the front and work to the back. only the upper trim)

find the point on the inner hatch where the wiring harness splits into its different connecters. add a few inches and cut it

do the same for the body connecters down by the right rear fender. they should go up by the tail light and go into the hatch (use your multimeter to check if your not sure

now pull the new wire through with that fancy weldingwire/coathanger. i had 9 wires in my 97 the upper brake light connecter doesnt go into the lock area of the hatch. it takes a sharp left as soon as it goes through the boot and goes directly to the brake light. the ground from the brake light went up into the lock area and connected to the main ground wire from the body.

now for the hardest part. wire it up.  I used a multimeter to check what wires went into the harness and then spliced matching colors. this worked for me just fine.
 

now put the battery on and make sure you dont get any BIG sparks. like the scary ones. (do this with your door closes and all the knobs set to off pop it on again and walk around the car and make sure theres no hot electric smells.

start the car and profit. it took me 2 days to do the entire procedure and i have no experience working with electrical stuffs