More problems with my coupe

[newsh]

Here is the diagram again.
My understanding is as follows.
The vacuum from the reservoir is connected to the rear diff controller all the time, the vacuum is always applied to the "hold off" side of the actuator, when you push the switch down the controller applies the vacuum to a different hose to pull the diff lock on. If you have no vacuum at all or a diaphragm is split it's possible for the diff to lock and unlock itself randomly. When the diff is in the locked position the light will come on in the "diagram" in front of the switch and the ABS will be switched off.

[twoqu]

Lou,

You need to physically move the lever to the disengageged position and tie wrap it to the bracket to stop it flopping about and re-engaging. At least for a temporary measure!

[4WheelDrifter]

Under the car, Lou. The diaphragm is inside the plastic housing Eric showed in his photo. You could try a couple of clean lengths of vacuum hose to suck/blow on, to check the operation.

[4WheelDrifter]

As you probably already know the light is dependent on the actual physical position of the diff lock mechanism. The switch is on the opposite side of the output flange. Bottom right in my photo.



As Robin says, cable tie the actuator arm if you need to keep it unlocked temporarily.