X5 horn not working - fuses keep blowing

[leafsrule531]

Hi - I have an issue with the horn in my 2007 x5 3.0 not working. I checked the fuse box and realized the fuse for the horn was blown so I swapped in a new one and tried it again. Fuse blew as soon as I pressed the horn. Any ideas what this could be or how I could fix it ? It’s really hard to drive in NJ a without a horn and prone to accidents.


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[ard]

likely one of the conductors in the steering column module (SZL?) has shorted to ground.

https://www.youtube.com/watch?v=Mk6QEPrg97Y



Just look at schematic and use a multi-meter to track it down.


your horn prevents accidents in NJ?!? Interesting.

[andrewwynn]

First bet would be in the wiring to the horn itself. Does the car use a horn relay or just electronics/transistors?

Which fuse is blown? There should be a high current fuse for the horn and low current fuse for the wheel electronics/clock Spring.

The only high current wires usually in a clock spring are for the air bag the rest are just control wires low voltage low current.


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[Zulu95]

Hope this helps:

[ard]

Thanks zulu.


The JBE can be a source of misery.... be aware than odd electrical failures have been traced to this.


OP which fuse is failing? you can disconnect one horn, then the other, to see if one of that has failed-short...

[leafsrule531]

Sorry for the late reply on this. I hurt my back playing tennis over the weekend and the unfortunately the pain has been brutal so haven’t really had a chance to look into this at all.

This is the website I used to check the fuse:

https://fusesdiagram.com/bmw/fuses-a...mw-x5-e70.html

According to the website there’s only one fuse for the horn which is located at F9. That’s the one I replaced and as soon as I tried the horn it blew and all I hear is a clicking sound when I press the horn. I did watch the YouTube video which you posted which was very helpful.

I’m not very electrical savvy at all so while the diagram was informative... I’ll need a lot more help to try to figure out the issue.


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[leafsrule531]

Originally Posted by ard

Thanks zulu.


The JBE can be a source of misery.... be aware than odd electrical failures have been traced to this.


OP which fuse is failing? you can disconnect one horn, then the other, to see if one of that has failed-short...

I don’t really have any other electrical issues in the car other than the horn not working so I’m hopeful that the issue is not the JBE since it’s pretty expensive.


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[Zulu95]

Isolate each section of the circuit for testing: Remove the relay, reset the fuse and press the button. If the fuse blows then it is not the wiring to or parts of the horns. (Doubt that will be it.)
Pull the connectors from the horns and put the relay back in and press the button. If fuse blows then it is the wiring. If it does not then connect one or other horn. Repeat test. If the fuse blows then that horn is faulty. If not it is the other horn. Replace both as a precaution.

[andrewwynn]

It's nearly impossible to be the electronics. It's almost certainly wiring. Rather than blow fuse after fuse just use Ω meter and measure the load side of fuse to ground it should be a couple ohms. If blowing fuses it will be well under an ohm. Likely means hot wire is grounded under a tiedown strap

[ard]

OP..so Fuse #9 is listed in that diagram.


You say you hear a click though? This is the thing labeled 'relay' inside the junction box in the diagram. Good news as this means all the circuitry is probably working.


There is either w wiring short or a short has failed internally causing it to draw too much current


1. Find each horn
2. Remove both wires from each horn
3. Replace F9 with good fuse
4. Try horn.
4a if fuse blows, it is a wiring issue
5. If fuse doesnt blow, attach ONE horn. Try again. If it blows, THAT horn is bad
6. If it doesnt blow, attach second horn. It should blow, that is the bad horn


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