Autoseatbelts Fixed!

There are three major wire bundles that control the seatbelts:

Connector 1 (Rear Limit switch bundle)
Yellow (Rear Limit switch 1 Signal)
Black (Rear Limit Switch 1's Ground)
Green (Rear Limit Switch 2 Signal (I belive it's a redunt switch for safety)
Black (Rear Limit Switch 2's Ground)


Connector 2 (Front Limit Switch Sensor)
Green (Forward Limit Switch Ground)
Black (Forward Limit Switch Signal)


Connector 3 (Seat Belt Motor wiring)
Black (Motor Forward)
Red (Motor Reverse)

--------------------------------------------------------------------------------
Basically with the key in the ignition both the yellow and green wire (the rear locked limit switches are reading 10V), and when this happens the seatbelt works, 12V to seatbelt motor)

With the key removed from the ignition the yellow and green wire read (.26V), and the seatbelt doesn't work, no 12V to seatbelt motor)

MY THEORY
So it seems like when the key is removed from the ignition, power is killed to the rear locked limit switch. With no power the seatbelt computer isn't recieving a signal from the limit switches saying the seatbelt it reatracted (locked) thus it doesn't fire the seatbelt motor to let you out. Seems logical.

I just wish somebody had an electrical schematic, it would make this so much easier. I'm going to rip apart my passanger side today to see what it does.

[alia176]

You know, I'll take a look at my ETM (elec troubleshooting manual) tonight and apply your theory. If I had a scanner, I could scan the pages!

Which direction (fwd or rev) does teh motor have to go to let you out of the car? I assume +12V?.

Ali

All DC Motors to reverse direction you just apply a negative voltage through them. SO basically the wires going to the motor will be this:

When seatbelt is moving towards windshield
black 12V
red 0

When seatbelt is moving towards seat
black 0
red 12V

One goes makes the motor go forward the other makes it go backwards.

[curlykicker]

Originally posted by 96svxer
There are three major wire bundles that control the seatbelts:

Connector 1 (Rear Limit switch bundle)
Yellow (Rear Limit switch 1 Signal)
Black (Rear Limit Switch 1's Ground)
Green (Rear Limit Switch 2 Signal (I belive it's a redunt switch for safety)
Black (Rear Limit Switch 2's Ground)


Connector 2 (Front Limit Switch Sensor)
Green (Forward Limit Switch Ground)
Black (Forward Limit Switch Signal)


Connector 3 (Seat Belt Motor wiring)
Black (Motor Forward)
Red (Motor Reverse)

96svxer, where's Connector 2 located?

Connector two is located with all the others below the rear window. Might have written the colors down wrong? It's the larger guage (smaller wire) two wire connector. it runs along the top of the window to the limit switch mounted near the windshield.

Well it seems my theory is wrong. My passanger side seatbelt works fine, and the rear limit switch reads 0V with the ignition off. Actually the rear limit switch has nothing to do with the seatbelt operation after the igniton is turned off. You can actually unplug the harness to it, and the seatbelt still works fine. So?????

I tried tracing the seatbelt motor wires back to see whats controlling them (they are a smaller guage wire so I thought they would be easy to trace.) I looked near the fuse box in the drivers side kick panel for about 1/2 an hour with no luck. Then decided to cut the tape around the loom to see which direction the wires are going...they are actually headed towards the back of the car???? so I rip out the trunk paneling, the wire loom heads from the bottom of the trunk, towards the top, and it looks like it runs along the bottom of the rear windshield. I assumed they were heading for the passanger kick panel, along with the passanger side motor wires. But could not find either in the kick panel. Withought gutting my cars interior in 15 degree weather, I'm not going to have any luck withought a wiring schematic.

Dont Give up. I have been reading this thread with anticipation, hoping to cure my own lazy driver seatbelt. I feel that it is at a climactic point in the story and am eagerly awaiting the next installment.

[alia176]

A'right dude,

I got the schematic. Finally had time to work on the SVX tonight. I'll scan it for you, 96svxer, and send you or anyone else a copy. This system is very complex at a quick glance. There's the ecu for Automatic shoulder belt system and everything else is being from it. This ECU is located under the rear wiper motor (rear deck) area.

Once we both the schematic, we can talk about it more intelligently. Send me an email so that I can return it with a schematic or two.

Ali

I guess thats explans why I lost trace of the wire loom under the rear window. But i swear the passanger side setbelt motor wires head towards the kick panel? Maybe they do a loop around?

Orthopodsvx, dude your post sounds dirty.......but funny.

All right but if I get frost bite...

thanks those schematics are going to help alot. Yeah I was surprised how complex this system actually turned out to be.

[alia176]

Dude,

Your profile doesn't have an email address and the link you have didn't take me anywhere. Send me an email and I'll send you the schematics. This goes for everyone who might want a copy.

Ali
alia176atyahoodotcom

[alia176]

Ok dudes,

I finally pulled my head out of my nether region and decided use my locker! Duh! Anyway, I posted the pdf schematic and a few jpgs of the automatic seat belt system. Hopefully this will help out a few people, including myself!

Party on,

Ali

Looking over the schematic, looks basically what I thought it would. The passanger side wiring loom doese run forward, then runs across the floor into the trunk, not the kick panel. Those crazy subaru engineers. Other then a bad " automatic Shoulder belt control unit" everything in my car I have checked and seems like it's ok. Except there is a seatbelt switch I did not know existed, it's actually located inside the seatbelt buckle near the emergency brake. Kinda wierd that there's only a driver side one. I'm guessing there might be small internal relays inside the control unit that have gone bad explaning why only one side has gone bad? My money's on a bad control unit. Anybody have a working one I could "Barrow"?

PS: alia176 that link wasn't a website, that was my e-mail address. just paste into your email.

[alia176]

I'll take a closer look at this thing tonight at home. Too many damn meetings at work today!

You can easily rule out the ECU by switching the wires from the driver side to the passenger side. If the same problem occurs on the opposite side, then you can concentrate your troubleshooting further on the ECU. However, I suspect it's a relay or some other high wear item that's gone capoot! The driver side is a highly used side and bunch of other SVX are experiencing the same issue. Furthermore, if your ecu is bad then you would have recieved an indication of such from the seat belt warning icon in the instrument panel.

To be continued....

Ali

[alia176]

Just in case you're wondering where the power is coming from in the schematic:
FB-8 (#22) - always hot
Fb-28, 30, 29, MB-2 - ignition

Here's what I'm thinking for troubleshooting: you'll need a second person to open and close the door while you're at the truck with a DVM at the ECU. I'm going on the assumption that the driver and pass sides are symmetrical and identical in operation. Voltage and continuity should be identical from both sides.

step 1:
Check voltage at Pin #1 and #2 while your helper opens and closes the door with ign on. Basically you're trying to establish a baseline. Make a note of the voltage as the motor is operating. do the same thing for the passenger side, pin #6, #7. They should be identical. Now close the door, turn IGN off and do the same thing for both sides. See if there's any diff between the driver and pass side. If the pass side is working and driver side ain't we can proceed to step 2. If the voltage is ok but the motor is not turning on the driver side, then let's move down to the connector at the motor.

step 2:
when the seat belt is out of the way, check for continuity between ground and #17 for driver and ground and pin #13 for pass. Sometimes when I wiggle the shoulder belt, it moves. Could be a coincidence but notice that the shoulder belt sw and rear limit sw are in the same connector. Also try to stop the motor from moving toward the rear of the car by creating a jumper between gnd and pin #17. If this works, then we know that the rear limit sw is doing it's thing.

step 3:
the front limit sw is a normally closed (NC) switch. Check for cont between pin #1 and gnd for driver, #14 and gnd for passenger. Perhaps this is being flaky and telling the motor not to start moving once the door is open. Try to mimmick this by opening up the connection between pin #2 and gnd before the belt reaches it's destination (moving toward the front). At least you can prove to yourself that the belt forward movment logic is correct.


Off to a mtg...to be cont...

Ali

I think all that you said was good, I've already done it. And after doing it I have realized that alot of that isn't nessasary (only found out after I did it).

The rear locked limit switch has nothing to do with the seatbelt retracting after ignition is turned off. (try it, disconnect the passanger side rear limit switch, I guarantee the seatbelt will still retract....So we can 99.99% rule that switch out.

I think we are looking for the same things, just in a different way.

I too thought I'd just switch the sensors from the passanger side to the drivers side, unfortunantly withought cutting and splicing your harness this is impossible. And just moving the sensors is impossible because they are mirror images of each other. Plus I measured all the sensors and both sides matched. Basically the problem is the ecu doesn't spit out 12V to the seatbelt motor to make it spin when it should. Why nobody is sure yet.

Also you think it's a relay thats gone bad, I'm kinda leaning towards the ecu.Well took the ecu apart. (yeah that was not fun) The instant I took it apart I noticed 4 small square devices, that reminded me of relays I used in college. Ran the part number through . (NEC MR331-N3) Well NEC Makes relays. I'm guessing there are two per motor (One to switch voltage forward, the other to switch the voltage negative). No way to tell if they are good, they are in a printed circuit board. Only way to tell is to swap a known working ECU into place. And I dont have one!

My only question with it being a relay is, why does the seatbelt work when the ignition is on? You would think if it's a relay it wouldn't work at all?

[fasteract]

I've been following this discussion with interest since I have had the "syndrome" of "driver's belt will retract if key "ON", door open" for a while. One thing I will add is that I have removed the door panel twice and gotten the mechanism to function correctly by adjusting, pulling the wire bundle near the forward upper door area as it dives into its sheet metal burrow. However, as soon as I reattach the door panel, it reverts back to fail mode. Is there a connector in this area ? Has any had this similar experience or wants to try it and comment ?

Cheers,

Craig