Problem with horn
 

Hello Fellow xB Gen 2 owners,

I am trying to diagnose a problem with the horn system in my car. Pressing the horn button on my steering wheel no longer causes the horn to honk. Just prior to the horn completely failing, the horn would respond to 2 or 3 button presses with wimpy honks.

I've checked the fuse (indicated in red circle of the attached pictureAttachment 19140) and it looks ok. I've also checked the low and high-frequency horns by hooking them up directly to the battery and they sound loud and proper. Using a multimeter, I have found that there is no power (no voltage) to the wire that connects directly to the horn. When I press on the steering wheel button, I can hear a clicking sound coming from the engine compartment fuse box and this would suggest that the horn relay is working. As the horn relay is not indicated on the fuse box lid (see attached pictureAttachment 19141), I actually don't know where this relay is located within the fuse box.

I think I've eliminated most causes of a faulty horn, except for the possibility of a damaged positive wire connecting the horn. I've tried to trace the wire to its source, but I'm having trouble figuring out where this horn wire leads to. Can anyone suggest next steps for me?

Thanks!

Have someone press the horn button while you feel the relays for the click to figure out which one it is. Then you can test the lines coming to the relay with the multi meter to see if there is power coming into the relay for it or not. It sound like either a blown fuse or a relay that has gone bad.

Hi Greg,
Thanks for taking the time to reply! Yesterday, I did give your suggestion a try. It didn't seem like any of the relays on the right side of the fuse box click or vibrated to the steering wheel button press. When I listened for the click, it seems like the sound was coming from under the 10A horn fuse. Is it possible the the horn relay is underneath the fuse and it is actually not visible from above?

It's possible but very unlikely. You might just have to try pulling relays to see if the click goes away.

I solved my horn problem! I found a break in the wire near the connector to the horn. So I basically repaired the wire with a new connector.

FYI, None of the relays on the right side of the fuse box relate to the horn.
The horn relay is actually under the 10A fuse (dark red shade in picture). To gain access to the relay, one must pull out the entire 'C' compartment (lighter red shade in picture).

Here is another shot of the Toyota relay integration unit indicating the part number. The price of a new unit is about $140 USD. I hope this is informative for anyone that needs to replay the horn relay. If the horn relay needs to be replaced, the whole relay integration needs to be replaced. These pictures are taken from a 2012 Scion xB.

Attachment 19148
Attachment 19149

Glad you got it fixed, but damn that is a stupid design on the relay.

glad to see you resolved this. enjoy your ride!

Can you tell me where you found your break in your wire. I am having the same problem.

Jesus, for $140 I would rewire the damn horns with their own relay harness, and never have to spend the $140 on a damn relay...