Wasn't sure if this went here or in the oily bits section but as it uses 'lectric and doesn't contain anything that can leak, this seemed most appropriate. For a while now my every time I hit a bump while turning left, I would get a beep, beep, beep and Bonnet Open would come up on the dash. The RH bonnet catch, the one with the switch in it, would sometimes stick too. After a bit of bouncing around on some lumpy stuff, it got worse and it was beeping at me whenever I turned a corner or hit a bump. Adjusted it so it opened and closed perfectly. Only problem now was that it was telling me the bonnet was open all the time. So I had a look at it.

Just under the slidey bit that latches under the pin, there's a bit of plastic. I poked it with a screwdriver and found it slides in and out and with it pushed in I could hear a microswitch switching. So I pulled the latch out to have a look. The bit of plastic is the end of a nylon carrier with a microswitch fitted to it. As it is pushed back by the pin the switch plunger hits a bit of metal sticking up from the latch body (or so it appeared). No problem, just put a bit of heatshrink sleeving over it to make it fatter and take up the wear. No, that's going to involve gong into the garage, finding a bit of heatshrink of the correct size, trying to shrink it with a fag lighter in a howling gale and it's just starting to rain. No, bend the bit of metal so it's closer to the switch so it doesn't have to move as far and it will all be good. Try to bend it with pliers but it won't move, it is a couple of mm thick after all. Get a pair of small Mole grips on it, give it a heave and it snaps off. It's not bent mild steel as it looked by the light of an LED torch, it's bloody Mazac! So, I've left it disconnected at the moment so it thinks the bonnet is always shut but at over 50 quid a go for a new one, I think the replacement is going to come from a breaker.

I haven't looked into the bonnet catches before, but I would probably (in your situation) look at just removing the faulty microswitch and mechanism and replace it with one of the switches with a metal lever on it, so as the bonnet catches, it trips the switch.

I'm not sure how easy it would be to do it - as I haven't looked at the bonnet catch mechanism to see how the switch mounts in a long while.

Can you post up a picture of the mechanism?

Not now as it's back on the car holding my bonnet shut, I just have no indication if it isn't at the moment. Not sure how easy it would be to mount, I'll have to have another look. It seems to be a really complex arrangement (would we expect anything else from Land Rover?). The plastic bit that sticks out into the hole where the pin/plunger thingy goes is part of a flat nylon spring loaded plate with the microswitch mounted on it with the actual switch button facing away from the latch. As the bonnet is closed, it causes this whole assembly to move and the button on the switch to press against the standing up bit of metal that I broke off. If the temperature rises a few degrees and it stops raining in the next couple of days, I'll pull it off and have another look and see what I can achieve (and get a pic or two)..

I've disconnected mine mainly to allow me to check BECM battery drain with the bonnet open ..,... is there a problem with this? (Apart from no warning that the bonnet is open!).

No, no problem... the bonnet switch is an activation input for the BECM, but with it unplugged it will just think that the bonnet is closed all the time, and thus won't 'wake' it up at all.

The BECM should still sleep with the bonnet open (switch still connected obviously) - it will chirp the alarm if you try to lock it as it's a mislock, but all the info out there on you need to have all the doors closed and/or locked and the bonnet closed etc to do the drain tests is bollocks. Especially on the later ones anyway. The BECM will go to sleep after about 2 minutes of inactivity - whether there's a door open or not. It's the change in state if you say closed a door, put the key in the ignition, opened the bonnet etc that then wakes the BECM up.

There is a list of 'activation inputs' in the BECM SID which are all things that will wake the BECM up from it's sleep mode - but they are all generally a change in state of something. If it's doesn't detect a change in state on any of the activation inputs, then it will sleep.

Marty

Interesting.

So, you can leave a door open fro example and the BECM will still sleep?

I think that's what you have just written, just checking!

Yes, it should sleep after 2 minutes of inactivity, whether there is a door open or not.

If you then close the door or trigger one of the the other activation inputs, then it'll wake up again.