Accord Coupe Alarm Misbehaving "FAULT"

[hughezee]

The moral of the storey where the alarm is concerned is anyway, I have come across several coupes with the alarm disabled including the remote locking by default due to the factory unit requiring replacement. Personally, I would disable it as suggested further up the discussion (since merged) by disconnecting the switch on bonnet latch as alarms are all too often ignored by people anyway, well unless its a neighbour battering your door down at 3am. Whilst the alarm is now silent you still have the advantage of remote locking and the protection of your immobiliser, which is all insurance companies really care about these days, unless your sitting on none factory wheels and will invalidate your cover at any opportunity during an unfortunate claim.

[welland99]

Over the years, I've had intermittent alarm issues on my coupe.  Just to recap briefly, sometimes the alarm would not set (evidenced by indicators not flashing when the car was locked), and sometimes when armed, the alarm would be activated for no apparent reason (evidenced by the alarm sounding and the indicators flashing).  

Several years ago I disconnected the alarm horn and left it at that.  I did consider disconnecting the bonnet catch switch, but never found the enthusiasm to do it.  In the intervening years, the intermittent problem persisted, but I just ignored it and no harm was done.

In the last month, things have got worse.  I have noticed the alarm silently going off a fair bit (evidenced by the indicators flashing), and also, the battery has sometimes been drained to the point where it won't start the car.  I'm pretty sure that the battery is fine, because sometimes it holds charge well, and other times it goes flat overnight.  That is not typical symptoms of a duff battery.  

Anyway, I turned my attention today to the bonnet catch, with the goal of disconnecting the bonnet catch switch.  In theory, this is a simple job, as there's a helpful plug to disconnect it.  In reality, it involves much knuckle grazing and contortion: more than expected for something that can be seen and seemingly easily reached.  Oh, and and the bonnet catch itself must be a contender for the grimiest part of the car with 20+ years of dried oil and grease mixed with 20+ years worth of road grime!

I've done the following:  

Removed the plastic cover around the catch - partly breaking it in the process (obviously).  Unbolted the bonnet catch mechanism, disconnected the pull cable to give better manoevreability, disconnected both horns, disconnected the sensor in front of the radiator (temperature sensor, I guess?), disconnected several plastic clips and brackets and FINALLY, got the bonnet catch sensor plug to a place I could get hold of it and disconnect it.  You wouldn't think it would take over 90 mins to do just that, but it did.  

Off to clean the bonnet catch, before refitting everything (except the bonnet catch sensor plug).

[Laird_Scooby]

15 minutes ago, welland99 said:

I'm pretty sure that the battery is fine, because sometimes it holds charge well, and other times it goes flat overnight.  That is not typical symptoms of a duff battery.

Surprisingly enough, those can in fact be symptoms of a failing battery, as can spurious false alarms from the alarm. However you appear to have found at least a fault bonnet switch, if the contacts are as dirty as the outside of the switch, they could easily cause a false alarm. I had a similar experience with an aftermarket alarm on a previous car, it kept giving false alarms until i renewed the battery (which until that point had always started the car the next day) and suddenly all false alarms were gone.

See how you get on now you've disconnected the bonnet switch, you may be fine and the battery is ok but if it still happens, consider renewing the battery, especially if it's an older one.

[welland99]

After I cleaned everything, I could actually see the switch.  It does not give the impression of being made for the harsh environment in which it is installed.  Although it is probably really cheap to buy, I bet it would be difficult to find one to fit.  

Anyway, I decided to test the switch with my test meter and I found that the resistance across the contacts was the same when the actuator was in both positions - no resistance (well, not actually 0, but not much).  Upon closer examination, I think that the switch plunger was stuck in.  

So, I put everything back together (leaving the switch disconnected), fettled the position of the bonnet catch so it actually catches thge bonnet, and all is well.  The battery didn't go flat overnight (as it did twice last week).  Maybe the problem is solved.   🙂

[PTR200S]

Excellent stuff !

Can you not free off the switch plunger with some cleaner or similar? Or has the spring bust !!

[PaulS]

I hate these awkward to get at things that are almost designed to go wrong.... 

Should you want to keep the original function, I wonder if  - as it appears to be a simple enough plunger on/off switch - whether a normal car door coutesy light switch might be a fair replacement?  You could adapt the wiring and mountthat switch anywhere suitable for ongoing maintenance.

 I once fitted such a switch under my bonnet (another car) so that a light came on under my bonnet once the bonnet was lifted.  That was still working when the car and I parted company.

[Laird_Scooby]

58 minutes ago, PaulS said:

I hate these awkward to get at things that are almost designed to go wrong.... 

There's logic in the lunacy though. At one point car thieves would attack the bonnet first to disconnect the battery and/or alarm before trying to take the car - if it's that awkward for the owner to access the bonnet switch, it will be more awkward for a would-be thief and therefore hopefully deter them into finding an easier target.

1 hour ago, PaulS said:

Should you want to keep the original function, I wonder if  - as it appears to be a simple enough plunger on/off switch - whether a normal car door coutesy light switch might be a fair replacement?  You could adapt the wiring and mountthat switch anywhere suitable for ongoing maintenance.

https://www.autoelectricsupplies.co.uk/product_list/45

Some options ^^^^^ others are out there and include longer versions that can be trimmed to length for use on bonnets, boot lids/tailgates.

1 hour ago, PaulS said:

I once fitted such a switch under my bonnet (another car) so that a light came on under my bonnet once the bonnet was lifted.  That was still working when the car and I parted company.

Nice upgrade and very useful!

[Andy Mc]

All sounds familiar the.. its just there but I can't get an angle or purchase on it, with the bonnet connector and super gunked up latch mechanism. 

Been there done that with the sliced knuckles from the rad being in close vicinity. Works as it should since though.

Funny I've done it on the actual car that the person who started this thread used to own.