Primathon

(crossposted at NASIOC)

So, I finally managed to kill my seatbelt chime once and for all. Turns out, it was easier than expected, although it ended up taking about an hour and a half (mostly due to how much time I spent upside down under the steering column).

Yes, I know there's a "put your key in and open/shut your door, then buckle/unbuckle the seatbelt 20 times in 30 seconds" method, but I tried that a half dozen times with no success. Plus, this gets rid of the door chime as well.

Under the steering wheel, there's a black box about 4 inches square with two groups of wiring coming out of it -- that's the Integrated Unit, and it's where that annoying chime speaker is located. Unplug the two cable connectors and remove the unit. On the 07 model, it's a friction fit, so you just have to slowly pull the unit straight down (mine took quite a bit of force to remove).



Once you have the unit out, it's time to remove the PCB. There are a number of plastic clips that need to be released. I found it very useful to fold up a couple small sheets of paper (~1/2" x 1") and use those as temporary shims to hold the clips away from the PCB faceplate.





After your shims are in place, remove the PCB and faceplate. I used a pair of pliers to grip the center of the grey wiring connector and pulling straight out. Here you can see the speaker -- it's the black cylinder about 1/2" tall at the top of the picture.



Taking a close look, however, shows removal of the speaker to be problematic. Subaru put a nice blob of glue around the base. Fortunately, we don't have to get rid of the speaker at all.



Flipping the board over, we can see the traces running to the piezo unit. There's a zener diode connecting the traces (labeled ZD3) doing something or other, so our target is going to be between the diode and the solder joint.

Using a dremel (don't bother with an X-acto knife) and a tiny griding/burring/whatever attachment, remove about 0.5mm of material from the surface of the trace. You can see the paint layer, the unetched PCB copper trace, and the PCB base material. Make sure to rupture the copper connection.



The next step is slap it all back together and plug that baby in. Sitting in the seat with the keys in and door open, you'll be greeted with a wonderful silence. The dash still flashes the seatbelt icon, but the "ding" is forever gone. Well, not really forever; applying some conductive paste over your dremel handiwork will restore the original function of the chime.

One thing I noticed after plugging everything back in is that my "check engine" light turns on when the key is moved to accessory power. However, as soon as the car is started, the light turns off and stays off. The problem here is that I never really noticed if the light came on before I did this mod. Anyone with an 07 want to check that for me?

 

ChopperMechanic

Ya the check engine light always comes on when you turn the key on. It's part of the self test.

Primathon

Thanks for the info