Faulty boot close sensor

[Norms]

Hi, I wonder if anyone could help me with a problem I have on my 8th gen Saloon. Recently I have had warnings while driving, that the boot is open but only for a few seconds. But lately when it rains (see below) it happens constantly and now every time I lock the car, within 20 minutes the alarm goes off. It has been a nightmare the past few nights and tonight my only solution so I can get some sleep, is to leave the bonnet slightly open so the alarm does not set. I have had an ongoing problem of a slight water leak in the boot and numerous trips to various garages have all yielded no fix. So I think replacing the sensor (wherever that is) at the moment wouldn't be wise. Is there maybe any way to lock the car normally but at the same time not activate the alarm? Or failing that, short the boot sensor so it thinks it is always closed?

 

[mlkehunt]

shorting it won't solve your problem if your loom is the culprit, but it doesn't cost more than a paper clip and some tape to try

 

[Norms]

shorting it won't solve your problem if your loom is the culprit, but it doesn't cost more than a paper clip and some tape to try

Thanks for the response, do you know exactly where to locate it and where to put the paper clip? Sorry I am not savvy with these, I pulled away some of the boot covering and found a little white plug going into the boot locking mechanism. I then put it back together just in case I broke something and the boot stayed locked forever.

 

[mlkehunt]

typically on the locking mechanism but sometimes also activated by a plunger or rod. but for the accord it's a 3 prong plug, it grounds through the body and one is for release signal and the other two are for the continuity check(I think)

the "easy" way to do this is to pry the shielding/casing open and visually inspect whether the striker within is in good shape. if it isn't, you can try to jump the terminals. test lamp and trial and error recommended. if you want to cut out the middle man, source a new lock

 

[Norms]

typically on the locking mechanism but sometimes also activated by a plunger or rod. but for the accord it's a 3 prong plug, it grounds through the body and one is for release signal and the other two are for the continuity check(I think)

the "easy" way to do this is to pry the shielding/casing open and visually inspect whether the striker within is in good shape. if it isn't, you can try to jump the terminals. test lamp and trial and error recommended. if you want to cut out the middle man, source a new lock

Thank you for that explanation. Electronics are baffling to me if I’m honest. I think replacing the lock with the current water leak may just recreate the problem down the line. You said something about using a paper clip, providing there’s no other problems, would shorting 2 of those pins make the car think the boot is closed all the time? I don’t even have a multi metre to test for continuity

My local garage doesn’t have space until the back end of the week. Leaving my bonnet open at least allowed some sleep last night but it’s a bit worrying doing that. Tricking the car into thinking it is closed would be ideal until I can get it looked at again.

 

[mlkehunt]

since the plug serves two functions I would make a test lamp with two lengths of copper wire, a paper clip and a 12v bulb, attach one end of the copper wire to a good ground like the locking bar and then probe one pin on the plug at a time with wire + paper clip, as you're using the keyfob to activate the release. you'll find out which pin makes the bulb light up and leave it well alone
then you would have to figure out if the sensor circuit works like in the picture above.

if a closed boot breaks continuity, cut one wire and isolate the two ends.
if a closed boot enables continuity, cut both wires and mate the two ends together
given the intermittent nature of your problem, you should be able to tell pretty quick from your dash indicator whether it registers as open or shut depending on which "fix" you try

a little more inconvenient, but if it works by breaking continuity of the circuit and you don't want to cut any wires, you could take the interior panel off and leave the plug unplugged. you'd only be able to open the rear with the emergency release, but it is an option

 

[Norms]

since the plug serves two functions I would make a test lamp with two lengths of copper wire, a paper clip and a 12v bulb, attach one end of the copper wire to a good ground like the locking bar and then probe one pin on the plug at a time with wire + paper clip, as you're using the keyfob to activate the release. you'll find out which pin makes the bulb light up and leave it well alone
then you would have to figure out if the sensor circuit works like in the picture above.

if a closed boot breaks continuity, cut one wire and isolate the two ends.
if a closed boot enables continuity, cut both wires and mate the two ends together
given the intermittent nature of your problem, you should be able to tell pretty quick from your dash indicator whether it registers as open or shut depending on which "fix" you try

a little more inconvenient, but if it works by breaking continuity of the circuit and you don't want to cut any wires, you could take the interior panel off and leave the plug unplugged. you'd only be able to open the rear with the emergency release, but it is an option

Thank you so much for going into detail for me, I really appreciate it!

 

[mlkehunt]

no problem, hope it works out!