Alarm Horn Problems

[Banshee]

It's not my week!!!!

Another weird issue with my truck, about a week ago my car did the strangest of things!!!! I was in the house and the alarm horn that is situated in between the inner and outer skin of the body on the drivers side behind the trim plastic just started sounding on it's own for no reason!!!! Not like a beep beep beep beep beep beep when the alarm is triggered but constantly on like someone holding their hand on the actual horn!!!!!

As you can imagine the neighbors weren't best pleased so I sped off in the car to a quiet spot near me and had no choice but to rip a battery terminal off as it was the only way of stopping the horn and it was loud

I took the trim off and disconnected the horn and tried another horn in it's place and at the time it didn't go off again, put the old one back on and again off it went constantly on. I presumed therefore that the horn was faulty and left it be for a while as I didn't have a spare horn to put in at the time.

I came to do the job last night and fitted a new horn that I've sourced, hooked it up loosely before putting the trim back on etc, locked the car, left the window down, waited for alarm to set then put my arm through the window to trigger the alarm, I had hazard lights but no horn sound :S

Straight out with the multimeter and tried again and find that it was pulsinng correctly as it should but was only throwing out a maximum of just under 3v out rather than the 12v needed to sound the horn

Video below, anyone got anymore troubleshooting ideas or what it could be? Where is the relay that controls the on/off for that horn?

 

[macabethiel]

Horn problems.

Whenever I have had issues with the Horn on vehicles it has invariably been the horn ring or the contact button.

Not familiar with the Nissan one but they are all pretty basic so often fault due to wear on either the contact ring or the spring loaded button.

If your horn is operated via a column switch then it might be a broken contact in the switch.

If the horn is part of your alarm then I am clueless !

 

[panelbeater]

its not his car horn but the extra one for alarm,mine is disconnected but hazard flashers work as cant seem to get fob working.yes done as it says in service downloads.

 

[emjaybee]

Whenever I have had issues with the Horn on vehicles it has invariably been the horn ring or the contact button.

Not familiar with the Nissan one but they are all pretty basic so often fault due to wear on either the contact ring or the spring loaded button.

If your horn is operated via a column switch then it might be a broken contact in the switch.

If the horn is part of your alarm then I am clueless !

It's not the horn-horn, it's the alarm-horn, situated between the rear boot trim and outer panel, as opposed to the one under the bonnet.

:thumb2

 

[Daemo]

well in the past I had a similar problem and it turned out to be a special low voltage horn specifically for alarms so I was told, I was also told that a normal volt LED will not work for an alarm as again low volt... this was years ago but could still be a consideration.

 

[Banshee]

well in the past I had a similar problem and it turned out to be a special low voltage horn specifically for alarms so I was told, I was also told that a normal volt LED will not work for an alarm as again low volt... this was years ago but could still be a consideration.

That's a good shout!!!! I my have a look in the workshop download if I can understand that section to see if it states any voltages.

If this is what it turns out to be then there's deffo a drink coming your way buddy!!!!

 

[Banshee]

well in the past I had a similar problem and it turned out to be a special low voltage horn specifically for alarms so I was told, I was also told that a normal volt LED will not work for an alarm as again low volt... this was years ago but could still be a consideration.

That's a good shout!!!! I my have a look in the workshop download if I can understand that section to see if it states any voltages.

If this is what it turns out to be then there's deffo a drink coming your way buddy!!!!

 

[Banshee]

So I had a look at this again last night while I was out doing a few jobs on the car with a new alarm horn from another Terrano. I was filled with hope at the idea these may have been low voltage horns but no such luck.

I noticed on the side of the new one that it did in fact state 12v

Tested the voltage across the terminals again and now it appears to be even lower than before struggling to reach 2v at best :doh

Does anyone know where the wiring routes back to? Does it go to an alarm box somewhere? I'm going to trace the cable back to the source hopefully and test voltage at the other end. The NATS and Alarms sections of the workshop download scare me though

 

[emjaybee]

So I had a look at this again last night while I was out doing a few jobs on the car with a new alarm horn from another Terrano. I was filled with hope at the idea these may have been low voltage horns but no such luck.

I noticed on the side of the new one that it did in fact state 12v

Tested the voltage across the terminals again and now it appears to be even lower than before struggling to reach 2v at best :doh

Does anyone know where the wiring routes back to? Does it go to an alarm box somewhere? I'm going to trace the cable back to the source hopefully and test voltage at the other end. The NATS and Alarms sections of the workshop download scare me though

They scare me too! I know that factory alarm systems can be a problem, especially the NATS one being linked into the radio etc. Is it worth considering leaving the alarm horn off and fitting an aftermarket alarm system?

:nenau

 

[Banshee]

They scare me too! I know that factory alarm systems can be a problem, especially the NATS one being linked into the radio etc. Is it worth considering leaving the alarm horn off and fitting an aftermarket alarm system?

:nenau

I don't really want to go down that route, I want the existing system to work :bow :bow

I'm plucking up the courage to read the manual this afternoon :question

 

[emjaybee]

I don't really want to go down that route, I want the existing system to work :bow :bow

I'm plucking up the courage to read the manual this afternoon :question

Good luck.

:hide:

 

[emjaybee]

Meant to ask if there was any progress on the steering wheel? Wife keeps asking me.

:nenau

 

[Banshee]

Meant to ask if there was any progress on the steering wheel? Wife keeps asking me.

:nenau

Didn't see this mate, I did get it sorted though :thumbs
See here in my project thread - http://www.nissan4x4ownersclub.com/forum/showpost.php?p=313031&postcount=317

 

[Banshee]

Update

Right

I've spent some time this evening trying to sort this again and don't seem to be getting any further.

The alarm horn now reads 0v when the alarm has been triggered with a multimeter hooked up to it, so I've followed the diagnostics in the workshop manual and now need some advice.

Here is the procedure I have followed so far;

Here are my results;

Unplugged plug from and applied ground to U43 on the Timing Control Unit above the fusebox which didn't sound the Alarm Horn.

Removed the passengers side kick panel where the bonnet release is, and disconnected the Alarm Horn relay, measured the voltage on terminals 1 and 3 and got 12.56 volts

While it was disconnected I wanted to test the relay but this is where I've hit my snag and not sure what I should be doing.

I energised 85 and 86 with a 12v battery and was getting the click, but as a definitive test I wanted to measure the resistance across 30 and 87 & 87a but what readings should I get on them whilst the relay is energised?

I'm also wondering if lack of door switch would be causing my issue but that wouldn't explain why the voltage was dropping gradually over time.

This is a weird one and I want my alarm working again.

 

[solarman216]

30 and 87 with relay energised should read 0 ohms, 30 and 87a should read infinity, Rick

 

[Banshee]

30 and 87 with relay energised should read 0 ohms, 30 and 87a should read infinity, Rick

Thanks you Rick :thumb2 :thumb2

Should the relay be audibly clicking on and off whilst the horn sounds as I can't hear mine clicking

 

[solarman216]

have no idea if the relay you are looking is the one for your horn, best put meter set at DC v on 85/88 and see if you get a voltage to enrgise the relay, Rick

 

[Banshee]

have no idea if the relay you are looking is the one for your horn, best put meter set at DC v on 85/88 and see if you get a voltage to enrgise the relay, Rick

Should it be permanent or on and off from the signal received from the TCU? Surely it would click as the horn sounds?

 

[Banshee]

have no idea if the relay you are looking is the one for your horn, best put meter set at DC v on 85/88 and see if you get a voltage to enrgise the relay, Rick

It's def the one for the horn, I traced it as per the Workshop Manual

 

[solarman216]

if it is not clicking ether the relay is duff or it is not getting a signal to operate, try swapping a similar relay from elsewhere, Rick