Where is the horn relay?

Discussion in 'LR3' started by mvg, Mar 13, 2011.

Car Parts
  1. mvg

    mvg Member

    Posts:
    6
    Likes Received:
    0
    Joined:
    Sep 30, 2005
    bbyer,

    I undertand what you are saying about the truly bad horn causing the good horn to go bad. However, replacing the horn that went bad returns everythnig back to normal. Here's the sequence of events:
    1. Horn goes off continuously and burns fuse.
    2. Replaced left horn with new one.
    3. Both horns working for weeks.
    4. Horn goes off continuously and burns fuse.
    5. Disconnected right horn.
    6. Left horn (the new one) working alone for weeks.
    7. Left horn (the new one) goes off continuously until I remove fuse.
    8. Waiting to buy two new horns.

    Notice that the new left horn was on its own for weeks before it went off again. Coincidence or poor quality/batch?
     
  2. bbyer

    bbyer Full Access Member

    Posts:
    722
    Likes Received:
    64
    Joined:
    Aug 15, 2008
    Location:
    Alberta
    Would hope it is a bad batch.

    Yes, you are doing about all you can to separate the horns re testing.

    I can see why you think that there may be something wrong in the Central Junction Box. A bad batch of horns would be a nice simple answer.

    I gather the high tone horn, (YEB500170), and low tone horn, (YEB500080), are different as the part numbers differ. The reason I ask is that it puzzles me as since the horns are different, why is each horn on a separate feed out of the CJB; most other vehicles usually just jump a single wire from horn to horn, (but LR is always different, I know).

    Somehow I think that there is more in the CJB re the horn circuit than just a single relay type FET, a solder joint, and two output pins.

    While you are waiting for the new horns to appear, you might want to follow the ground side wiring and look at both the splice and the ring connector and ground stud. Sometimes if a ground is not grounding, odd things can occur and what you are experiencing is definitely odd. In this case, it is even harder to figure out as the problem is at best intermittent, as in once in a while every few months.

    At least the horn circuit does not appear to be tied into the air suspension and hence the drop to stops tantrum reaction.
     
  3. quartzsand

    quartzsand New Member

    Posts:
    4
    Likes Received:
    0
    Joined:
    Feb 25, 2015
    My 2008 LR3 HSE horn spontaneously went off continuously while I was driving yesterday. I think it burned out one or both horns as I was not able to locate and pull circuit breaker in time. Turning off the vehicle and removing key or cycling the ignition system on and off did not stop the sound, although I think there was a pause for a fraction of a second when I turned the ignition back on. Right before it activated I had briefly touched the lower cruise control button on the left side of the steering wheel. Then the audio command system gave the, “no audio command received” prompt- but I had not activated the audio command switch behind the wheel. While this might just be coincidence, I mention it as bbyer noted the clockspring located within the steering wheel hub was problematic and wonder if this might help point to the clockspring as being the root cause of this problem? As the horn continued to sound the pitch changed and then became a frequency I could feel in the pedals before dying completely. This makes me think one or both horns burned out (as opposed a circuit breaker cutting the circuit suddenly). After this horn malfunction the LR3 starts, but I have no horn, and the radio has also suffered a short/blown fuse. The clock is there w correct time and the backlight is on, but the radio will not come on and there is no response to any of the dash audio system buttons. I do see the link to horn system wiring diagram in prior post, but if anyone can put together what might have shorted or grounded and point me to which fuse blocks I should check I’d be greatly appreciative. Is there a way to diagnose the fault as originating from the clockspring? It sounds like I may need to replace one or both horns, but given other symptoms I do not think defect was primarily w horn.
     
    Last edited: Jan 25, 2020
  4. bbyer

    bbyer Full Access Member

    Posts:
    722
    Likes Received:
    64
    Joined:
    Aug 15, 2008
    Location:
    Alberta
    I assume you have two immediate problems - no horns and no radio.

    The horn thing I will address in a post perhaps tomorrow, but I presume that you have disconnected both where the conductors connect to the horn? If not do so.

    To get the radio and whatever else going, I am going to suggest what is called a Hard Reset per the instructions below.

    The good news about a hard reset is it costs nothing, does no harm, and sometimes resolves concerns.

    I find that after an alternator or battery change out, I sometimes have to do the same - think it has something to do with the car computers losing power before the computers have shut down - like pulling out the wall plug cord on a desktop computer when it is running. A hard reset is kind of like Control-Alt-Delete on a Windows machine.

    Hard Reset Instructions

    In brief, to start the hard-reset process, open the hood but close all doors and let your 3 go to sleep - no radio display etc and no key in the ignition. This will take a couple of minutes and do not open any doors until the reset is completed. (I find that it is often a good idea to have the driver’s door window rolled down and the key in one’s pocket whenever fooling about the vehicle.)

    Also, when I play with a car battery, I remove any rings I have from my fingers, also my watch. Have the car keys in your pocket.

    Disconnect the ground battery terminal from the main starting battery.
    Disconnect the positive battery terminal from the main starting battery.


    The reason for this order is if a wrench or loose battery cable ends grounds to the body, no arcing or other bad things happen.

    (I assume that you only have one battery in your vehicle. If not, disconnect the others as well and leave them disconnected until after all is done.) I have the Traxide dual battery system installed.

    Connect the negative cable end to the positive cable end. (NOT to the battery.) To do this, you will need a short length, (a foot or so), of light gauge, (14 to 18 gauge AWG, insulated stranded copper), wire to span between the battery cable ends as there is not enough slack in the positive and negative battery cables for the ends to be able to touch each other.

    Hold all together for about a minute or more, (suggest at least two minutes), as you are discharging memory modules within the engine computer and elsewhere. Then it is suggested you then just let all sit disconnected for say ten minutes, (minimum five minutes), prior to commencing to put the battery cable ends back on the battery posts per the following order.

    Reattach positive terminal to the main starting battery positive post.

    Reattach negative terminal to the main starting battery negative post.

    Start engine and hopefully none or at least fewer warning lights and the radio when turned on plays music rather than being silent.
    Reset time on the radio - note that the station presets are still there as not everything is erased. Nothing much else needs resetting either.

    You can also now connect up the other batteries if you have a multiple battery setup.

    This is a link to a thread in disco3 re the hard reset procedure. http://bit.ly/14WXXR1


    http://www.disco3.co.uk/forum/topic19547.html


    This is a link to a thread on Disco3Club re the hard reset procedure.

    http://www.disco3club.co.uk/phpbb/viewtopic.php?f=67&t=3374
     

Share This Page