Locked out of mk3

  1. My model of MX-5 is: 2008 Mk 3
  2. I’m based near: Huntingdon
  3. I’m looking for technical help or recommendations on: Battery flat unable to enter manually with key.

Hi I wonder if anyone can make a suggestion how I can gain access to my Mk 3, it’s the one with the electric tin roof. Basically I have returned after a month away and found the battery to be flat and door unlock was not possible with using the fob. I tried the key manually but it wouldn’t turn. Lots of WD40 and a pair of long nose nosed pliers on the body of the key and still no joy. The key does however unlock the boot perfectly and I believe at some time in the past I have opened the car manually with the key, so was surprised that it won’t open manually now.

Thanks in anticipation for any suggestions.

Are they aftermarket keys ?

I found that my aftermarket keys did the same - unlocked the boot and switch on the ignition but not unlock the doors.

I filed appx 0.5mm off the end of the key and it worked in the door lock ( and still worked in the boot/ignition )

I watched the AA guy use an airbag to ease the door glass out enough to reach in with a wire coathanger and operate the lock from inside.

As you can gain access to the boot, you may be able to reverse power the boot light to power the car up, depending on how handy you are. Where in Huntingdon are you? I may be able to drop by on my way home from work one evening. How urgent is it?

Thanks for your reply. I bought the car last summer with just one key. I believe it’s the origional.

Thanks Robbie, it’s not urgent, I’ve got other transport, just be nice to get inside and replace the battery and give her a good run, before the long overdue summer weather arrives! I’m actually in Eynesbury St. Neots. Whilst not massively handy I might be able to follow your instructions. Not sure if I’m allowed to provide you a mobile number on here…I’m a new member and not au fair with all the rules. Thanks for your kind offer to pop over, I’m just keen not to put you out. Regards Richard

Thanks I did consider buying an entry kit but on this model the rubber seal has a kind of extra thick section where the top of the window houses and I just feel there wouldn’t be enough flexibility to get the bag through and inflated. Cheers for the suggestion though

What’s your VIN, I’ll look at a wiring diagram and give you some pointers, you can decide if you want assistance.

Cheers it’s….JMZNC188200152633

Will have a look tomorrow evening. Had to go to the pub tonight for some reason.

lol, no problemo. Hope you didn’t drink San Miguel!

If you get the boot light trim off, there should be 2 black wires coming off the light. Follow those wires to the next connector along and you should find a Blue/Red wire and an Orange wire, disconnect this plug. Depending on what you’re using for power, apply 12 volts to the Blue/Red wire and put the negative side of your power supply to ground. This should power up the car and allow you to unlock it with the transmitter. Please let me know how you get on.


Robbie you’re a technical MX5 genius, yes you are! I followed your instructions as directed and within 5 minutes I was in. Chuffing marvellous, thanks so much! Had to laugh as whilst removing the battery rods that secure the battery in place, the front rod dropped off the nut and straight down onto the rad below…Uffff took me 5 times longer to retrieve the rod than it did to gain entry to the car lol. The clips I removed from the surround in the housing for the boot light didn’t want to go back in but they’ll be pennies to replace. Anyway many thanks again for your invaluable advice, I really do appreciate it. If we cross paths at an event at some point there’s definitely a beer with your name on it. Cheers Richard.


Thanks for the feedback. There is a knack to getting the clips back in but they will go.

That’s one of the best top tips I’ve read in a while. :+1:

I think @Roadie should have some of the credit, the concept was discussed recently and I went with powering the stop lamp bulb until I was corrected.


Put the clips in a mug of hot water for a couple of minutes (relaxed with the centre pin in withdrawal position), and you’ll find the splayed out fingers will return to their original closed position, almost like new.