MX5 central locking gone beserk!

[tango2]

I've got a 2005 MX5 Icon, and it's central locking has just started to go absolutely beserk - it won't operate via the remote at all, after opening the door with the key you have to catch it on the first 'open' then it open and closes the locks by itself. When driving, it goes into the phamton rapid open/close of locks intermitantly, always ending on locked. At your destination, you have open the window, let your self out using the key from the outside, open door (goes into phantom mode), then shut door - more phantom mode ending on locked.

I left the car today, and it started to go into open/lock rapid phantom all by itself - ended up locked, did a second round so quickly it sounded like the car was ticking over. I think it did a round of these overnight as when I went to it this morning it was open, having being locked when left - but usually locks itself.

Sometimes the indicators flash, usually not.

Any help/ideas please?

[fivealive]

Hi What make of alarm is it you have . . . Mine is a Toad alarm and immobiliser, and had a similar problem. After much searching the problem turned out to be a bad earth on the bonnet sensor, as simple as that, a good clean to creat a good earth and squirt with WD40 sorted it. Check also the boot sensor and do the same, if fitted. Just a thought, I may have been lucky, failing that it may be a job for an auto-electrician.
Phil

[tango2]

Thanks - typically I've booked it in to be looked at, and she's behaved impecably on the way home!

I think it may be a loose sensor - but haven't a clue where to start looking...

[fivealive]

Hmm . . . Well the sensors on my 5 are thus . . . one under the bonnet on the battery side, it looks just like a small black spring-loaded plunger next to the inner-wing, this is compressed when the bonnet is closed. This sensor was the one that wasn't earthing properly on mine. The other is located in the boot on the left hand side as you look at it and works in the same way. The motion sensors in the interior are mounted just above the armrest and the adjuster box for sensitivity is just visible through a small hole in the rear parcel shelf carpet with the eye of the sensor looking forward into the cabin. Of course different manufacturers and installers my choose different locations. But its worth having a good poke around before handing it over to a specialist. I made several enquiries on costs before handing mine over but none would give me a quote, which could mean a blank check if they have to sit around several hours waiting for the alarm to malfunction. I was lucky finding the fault myself . . . hope you are too.

[jdavies91]

Hi tango2

Did you ever get this issue sorted as mine is doing the exact some thing and its driving me crazy! I've had to take the fuse out for the central locking to stop me wanting to smash the windows!

Any input would be amazing

[leon29]

Hi jdavies91 and others,

Did you ever manage to sort your problem?
I bought a mx5 mk2 2004 back in August and its been sitting under a car cover for a few months until I can drive it with one-year-no-claims, and everything was fine until I had to change the battery as it completely died.
Central locking was fine the day of the battery change, however a week later when I went to start up the car the central locking started going haywire.
Press the unlock button on the key and it unlocks for about .5 of a second before locking again. Same with unlocking manually, as soon as the key returns to neutral position in the door lock it locks again. When I manage to get the door open in that .5 seconds, you can see the door lock locking and unlocking frantically until the door closes.
The lock button on the remote does not work either. (Have removed the car key battery to make sure the key is not playing up but car still has the same problem, so not the key).
Sometimes the car alarm will randomly go off, even got locked in the car recently haha.

I know this is an old post but any help would be much appreciated, auto electricians cost too much.