Horn relay location (1 Viewer)

[Roadhouse1]

Hey all - finding the horn relay is driving me insane!! Can anyone shed some light as to its location? Have a right hand drive 2003 100 series (UZJ)

Found the fuse easily enough in the main fuse block under the hood but couldn't see a relay there.

Is it behind the fuse panels in the drivers or passenger footwell? Couldn't see it but maybe behind the loom(?) panels?

Any other location?

TIA

 

[planomateo]

From the 04LC FSM

The horn relay is built in engine room junction block. Also the relay is constructed with a relay block that is in the junction block as a unit. To disconnect the wire harness connecting with relay block is impossible. If the relay has a malfunction, replace it with junction block assembly wire harness together.

 

[Roadhouse1]

thanks PlanoMateo. Will have to think of another way around perhaps.

The Stebel nautilus I am installing calls for a 20A fuse whereas existing circuit is only 10A. Given that presumably I can't access the horn relay, I was thinking of simply swapping out the 10A fuse for a 20 and using existing wiring. However, the new horn calls for 2.5mm2 wire from relay to horn and I'm sure the existing wire is nowhere near that big so I am running the risk of a melt down if I can't get to the relay. Have seen other posts saying existing wire is fine but in not so sure.

Other option is to install an entire new circuit but would rather not.

Time for a(nother) beer and some thinking music...

 

[Dwight S]

The relays are on the back of the fuse panel. It can be removed. The wiring harnesses plug into the panel. A friend of mine had it out in about 10 minutes.

 

[Roadhouse1]

Do you mean it is underneath the main fuse block under the hood? Or behind passenger or driver footwell fuse blocks?

 

[Dwight S]

On US UZJ100, left hand drive, it is on left footwell fuse box. You have to remove the fuse box to gain access. See this trend for more information.

2001 fog light issue

 

[Roadhouse1]

On US UZJ100, left hand drive, it is on left footwell fuse box. You have to remove the fuse box to gain access. See this trend for more information.

2001 fog light issue

Ta - some great info there.

Have been looking at the FSM and found the quote planomateo provided and I now understand the 'Chinglish' a bit better. It seems the relay is under the engine compartment fuse box. Will try and prise off the fuse box to see what lurks underneath. Hopefully will see a horn relay of some sort there and can do what I need to do.

 

[planomateo]

Funny, only reason I even knew this was because I was looking up the horn info for someone else, I was trying to track down the relay. I've never pulled that fuse box. Post up some pics if you get it pulled up so it will help others out in the future.

 

[Roadhouse1]

will do. Have been googling some tips for doing it and will be an interesting experience me thinks!

 

[Roadhouse1]

change of plan after speaking to my brother who is a sparky - leave everything where it is and just use the existing horn wire at the horn for the feed into the new relay to give it power and run all the usual wires needed to wire up a new horn - simple!

Solves the issue of using the crappy (undersized) existing horn wiring as a plug and play on the new horn (potentially a meltdown problem), but most importantly it saves me having to dig around into the depths of the engine compartment fuse block to find a horn relay. Winning...

To do the job:

- mount a new relay somewhere nice and dry...
- run the existing horn wire to pin 86 on a new relay,
- run an earth to pin 85,
- run a new (correctly sized) wire with a 20A in line fuse from the battery to pin 30,
- run a wire from pin 87 to positive terminal of new horn.
- run a wire from negative on the new horn to an earth to complete the circuit.

Worked a charm. Hope this helps others looked to upgrade to improved horns.

So apologies - no pics of getting the fuse junction box apart, but the above has saved me a hell of a lot of time and effort.

 

[PHIL O]

resurrecting this thread fellows. i just bought a stebel. i am doing as you suggested above but would like to simplify the circuit by canceling the original horn relay. once i remove the original horn relay, i will trace the negative horn switch and connect a jumper to the wire going the horn unit making it an extension of the negative horn switch.and connect this to 85 on a bosch relay that i will mount at the grill. from positive battery i will connect 30 and 86 on bosch relay. and connect 87 to horn positive and ground the horn negative.i would like to cancel factory relay to simplify the circuit and making future diagnosis simpler. would this be feasible?

 

[vcheng]

Do you mean it is underneath the main fuse block under the hood? Or behind passenger or driver footwell fuse blocks?

Go to page 2 for photos of the innards on the main JB:

2005 LX470 Main Junction Block Replacement

 

[Roadhouse1]

You could def do this but a lot of work involved. Haven't had an issue with mine the past 12 months it has been in so not sure all the effort is needed? You could always just do as I did and if there was a problem down the track you could then do all the rooting around to check out the original horn relay as part of any future issue diagnosis?

 

[eurodre]

You could def do this but a lot of work involved. Haven't had an issue with mine the past 12 months it has been in so not sure all the effort is needed? You could always just do as I did and if there was a problem down the track you could then do all the rooting around to check out the original horn relay as part of any future issue diagnosis?

I'm gonna resurrect this as well:

I have an lx470 with 2 stock horns(high and low). After I cut the horns do I bring both of those stock wires to pin 86? Or is there a way to find out which one is a + and - ?