2015 Yaris 1.3 vvti Horn problem

[Shivers]

When I switch of my car the horn sounds and I have to remove the fuse.  Is there a fix fix for this?

[Shivers]

I have cleaned all earths checked all connections checked relay and still the problem with the horn persists.  When I turn off the car the horn starts and will not go off and I have pulled the fuse to stop the horn from working which is not ideal.  Has anyone here had the same problem ?

[Bernard Foy]

Does it work normally with the ignition on??

[Shivers]

Hello Bernard no, if I press the horn it will not stop at all and I have to pull the fuse.

[flash22]

Does the horn work while driving the car ? turn the steering wheel to the left or the right before you turn the car off, does it still go off ?

[Shivers]

Hello flash22:  No the horn will just not turn off when I turn the ignition off.

[Shivers]

When I replace the fuse and press the horn it will not stop sounding.  I have to remove the fuse again.

[Mooly]

First question. 

Has this worked correctly in the past and suddenly gone faulty or have you just got the car and it has an unknown history?

 

[Shivers]

It has worked correctly up until a couple of days ago.

 

[Shivers]

Have been told that I will have to replace Part Number 82641-52020 Fuse relay holder.

Just was hoping some0ne here could help me with this problem, I am sure others would have the same happening to them.

 

[flash22]

ok remove the steering column cowl - turn the wheel to the left to access 1 screw and turn it right to get to the other and there is one in the bottom

unplug the clockspring plug (ignore the arrows )

 

See if it still sounds

[Mooly]

16 hours ago, Shivers said:

It has worked correctly up until a couple of days ago.

So it appears to be a genuine one off fault then.

The way I would approach the fault is to first of all disconnect the horn so it doesn't keep sounding and confirm that you still see 12 volts across the now disconnected horn wires. You could even connect a 12 volt bulb in place of the horn as a visual test indicator.

Next I would find the horn relay and check that the 12 volts to the horn is only present when the relay coil is active. That means 12 volts applied to the relay coil.

RELAYS

If the horn is active without 12 volts applied to the relay coil then the relay is faulty. If you pull the relay out then the horn should stop. If it doesn't a wiring fault (like a short) is applying 12 volts to the horn directly. 

If the relay coil has 12 volts across it when it should not (horn button not pressed) then either the horn button is faulty or there is some other wiring issue applying the relay coil voltage from elsewhere.

 

 

[Guest]

With the horn having a permanent 12v without ignition on, my primary suspect would be a stuck relay. With the main supply contacts permanently engaged. Could be worth locating the horn relay and giving it a few light taps, when the horn is sounding, to check if it might "unstick" the contacts. If the horn stopped sounding when doing that, it would be a reasonable expectation of a faulty relay. Don't ask me where it is located! Presumably in one of the fuse boxes?

[flash22]

The horn relay is built into No. 1 integration relay, and lives in the main fusebox - as the OP posted above (82641-52020) - the same fuse supplies both the feed and control, the horn relay is ground side switched (control side)

Pics for reference

https://www.ebay.co.uk/itm/38398710137

 

by unplugging the Spiral cable aka clockspring it splits the circuit - if it stops sounding you know it's going to be the switch, wiring or spiral cable, if not it's the Integration relay - a no cost way to diag the horn without throwing parts at it

 

[Starensis]

My previous 2005 Yaris had a bad water leak down passenger side footwell ( Behind Dash ) due to unsealed panels. Check you don't have the same around your electrics.

[Shivers]

Tried all help advice given above, problem still there.  Friend put car onto OBD Reader and it showed no codes.  Just have to bite the bullet and take it to dealers.  There goes this months pension.

[Mooly]

Let us know how you get on. Good luck. 

[flash22]

Swap the integration relay, it's just a case of unplugging it and popping it out of the fuse box