How To: Central locking fault (Now fixed)

thought I'd share my unusual experience recently when my central locking became faulty by being able to lock together but wouldn't unlock together.

As we know both the solenoids and control unit are prone to become faulty but upon some testing with a test light I wasn't convinced....

My findings found that the brown/ silver (lock wire) earth signal wire was switching fine when operating the locks manually, but the brown/pink (unlock wire) wire was constantly earthed no matter if it was locked or unlocked...

Ah! I thought, must be the switches inside the doors!?.... Nope! upon inspection they were operating perfectly,

So I grabbed the lock wiring diagram followed the brown/pink wire and realised straight away what was at fault...
http://uploads.tapatalk-cdn.com/2016...d148b96ee7.jpg

The inertia switch under the dash was at fault!, on unplugging it the central locking returned to perfect working order

http://uploads.tapatalk-cdn.com/2016...5a2639dfce.jpg

I've ordered a new inertia but whilst I wait simply bridged the fuel pump wire..

http://uploads.tapatalk-cdn.com/2016...4d5f712543.jpg


Thought this might be helpful to people as it's prob the last place you'd think to try before replacing expensive components.

Cheers

thanks for the post, finally I can show it to people without having to explain it myself over and over...

Wait... Im confused. My locking system seems to go haywire at times and it drives me mad. You're saying it may be the inertia switch? Where exactly is this located. Is it expensive??

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The inertia switch lives in the drivers footwell, on the upper left-hand side behind the carpet. It's a small black box with a plunger that should be pushed down or the fuel pump will not operate. This thing: http://store.delorean.com/p-7047-inertia-switch.aspx