The ABS is not good off road, especially on gravel tracks.  The ABS is automatically switched off when you select the centre differential lock.  However, I have found the truck to be great on tracks without the centre differential lock engaged, which is mainly due to the torque splitting centre differential doing a great job.  Without the centre differential locked engaged, there is less strain on the transmission and the tyres.  On our travels I often come across sections of road that are continuously switching between on-road and off-road conditions.  I therefore wanted an ABS disable switch – a way to quickly turn the ABS on and off without having to use the centre differential lock.

When the AFAM (differential lock management control unit which is under the left seat) wants to turn off the ABS it supplies an earth, on the green wire number 8142, to the K4 relay coil (note: in the vehicle handbook, the K4 relay is listed as relay No. 6 ‘ABS Relay’).  I have therefore cut this wire and inserted a small diode between the AFAM unit and the relay coil. 

I have also attached another wire to the relay coil side of the diode that I can switch to earth whenever I want to turn off the ABS.  The diode is simply to protect the AFAM ECU when I earth the relay coil with my switch.  My switch uses the AFAM’s ABS relay, which means that the ‘ABS Failure’ and ‘ABS’ lights come on when I turn off the ABS (in the same way as they do when the differential locks are engaged).

I can now simply switch the ABS off and on as required by the road conditions, regardless of the centre differential lock.  If the centre differential lock is engaged the AFAM system still turns off the ABS automatically.

Click here for other Modifications and Repairs done to Cuthbert our overlanding truck

Hey… was this useful? If so, you might like to support our website costs with a donation below. Thanks 😊👍