Factory Diff Lock

[XLR8]

I have factory diff lock in my GQ and the actuator isn't engaging. I have I have heard that the solonoids are prone to problems so first thing I did was run a couple fo tests to make sure there is vaccuum to the solonoids and power supply. There is good vaccuum so that is not the issue. When switch is OFF there is power to one of the 4 pins on the solonoid but in ON there is none. Apparrently these have quite a complicated circuit although there is nothing at all about them in the FSM. anyone have any ideas or experience with these.

Cheers in advance,
Mike

[AB]

Just for a quick test...

I would be checking the earth on the solenoid.

You will always have 12v going through the solenoid. The switch "should" make earth to power the solenoid, etc.

If the earth to chassis is rusty or not connected, etc then this would be the reason why you don't have power once the switch is turned on.

Worth a quick look anyway...

[XLR8]

Cheers AB, went through it today and found the problem. There is a control unit screwed to the framework behind the stereo/switch console and the plug was loose/out. plugged it back in and all working sweet.

[oldtimer40]

I have a GQ with factory diff lock also - and it appears it is not working, switching in both 4H and 4L modes - and nothing.

There is no info in the factory manuals I have.

I know where the solenoids are under the dash, all the hoses seem to be in good condition leading all the way down to the rear diff unit itself.

Been reading here the solenoids are a common issue, as the LOCK-OFF solenoid is always ON burning out the solenoid coil - this I can replace if necessary.

- How do I check if the vacuum is present and where does it come from?

- How easy is the access to this solenoid control unit behind the radio panel?

Will be going bush next weekend, and it may come in handy...

[SKID]

Did a google for MAC vacum solenoid found their distributor in Brisbane Part number is 45A-AC1-DDBA-1BA the "-M532F" is for a mod on the standard one which makes it water proof, cost including fittings was 112, the one mentioned previously in the post from melbourne wanted over $200. works a treat now...