Interior central locking switch

[DrasticplastiC]

Please can somebody with experience help? My central locking switch on top of the central ball door opener no longer works, nor does the light illuminate. If I connect two of the three wires together with a probe wire the light illuminates green, so it receives +12V and earth. What could the cause of this be? I have tried to test the switch for resistance but it appears permanently closed. Or perhaps testing the switch with my multimeter on buzzer setting was too blunt to detect the microswitch open...

[Belle427]

Perhaps it’s just stuck in the on position, you should be able to test it.
Does the locking work as normal with the alarm fob?

[Wolvesboy]

Jeez, I didn't even know this was for the central locking! Needlessly to say it doesn't work anyway!!

[Belle427]

You normally remember it when you keep resting your arm on it and the doors lock!
Maybe some cars have it disconnected if an aftermarket alarm has been fitted that has the anti hijack feature enabled.

[Steve_D]

First off the button only locks the car it does not unlock.

Your button probably is wired with a connector less than a foot from the knob. the wire colours at the connector are:-
B/W to W
W/G to G
B to B

B is the earth.
So apply +12v to the green should light the LED.
Test White to Black should give open circuit until you press the button.
While you are there short the B/W to body earth should lock the doors.

As an asside the door locks use 5 wire solenoids (1 wire is not used) the only reason for the extra 2 wires is to light the LED. Often the LED does not work if one of the solenoids is not adjusted correctly and is being held in a slightly 'Unlocked' position or it bounces there after the lock motion. This circuit is only live with ignition on.

Steve

[sixor8]

It's for security really. So that nobody can walk up to the car and open the doors when you are stationary.

It failed on my last Chimaera but the little switches were pricey, and fiddly, so I lived without it working.

[DrasticplastiC]

Thanks for the advice. Yes I got the doors to lock by connecting b/w to b. If I locked the doors on the remote as opposed to leaving them unlocked, on touching w/b +12V to green not only did the light on top of the know illuminate but so did the indicator lights and oil pressure / alternator lights! So that's what you're not supposed to do evidently...

On the face of it then it looks like a duff know switch and a central locking electrical fault not lighting up the knob button light.

I have noticed the door switches for the interior light are not workin properly, the light is permanently on in both switch directions. Could this be related?

[DrasticplastiC]

PS I did the above with the ignition off, so I have a live feed to the knob with the igntion off.

[Belle427]

They are a common issue so worth checking them.

[QBee]

Re the interior light and the locking, yes, they are connected.
The pin switches in the door sills both activate the interior light and tell the alarm system that the doors are properly shut.
Worth cleaning them up.

[DrasticplastiC]

Thanks, I've cleaned the door contacts, those and the light are now fine.

The knob switch does not lock the doors ignition on (does the engine have to be running? I doubt it) and the green light is still dead.

I checked the door lock gubbins on both sides and lubricated with WD40, I couldn't see any obvious issues.

It's a mystery. Looks like I need to check the door solonoid off positions then?

[QBee]

DrasticplastiC said:

Thanks, I've cleaned the door contacts, those and the light are now fine.

The knob switch does not lock the doors ignition on (does the engine have to be running? I doubt it) and the green light is still dead.

I checked the door lock gubbins on both sides and lubricated with WD40, I couldn't see any obvious issues.

It's a mystery. Looks like I need to check the door solonoid off positions then?

Might just be a broken wire near the knob. That centre section is not too difficult to remove. Screws under the triangle at the rear end and also at the front corners

[DrasticplastiC]

Good comments thanks. The switch does not work, so that could either be the switch or the short wire to the plug. But this doed not answer why the light does not work in tendem with the rest of the car....