LR3 CJB Removal and Sunroof Drain Repair

LR3 CJB Removal and Sunroof Drain Repair

Important Note: Repair of the sunroof drain on the right hand side of the Land Rover LR3 requires that you remove and replace the Central Junction Box. Removing and replacing the CJB with the same CJB does not require reprogramming, but if you are changing out the CJB with a different one, new or used, you will need to reprogram the LR3 computer to communicate with the new CJB. The LR3 CJB has several electrical connectors that can cause problems if the pins are bent or damaged. Be careful when working on the Central Junction Box!

The electrical connectors on the CJB: There are six electrical connectors. 3 large connectors on the front, 1 connector on the bottom and 2 connectors on the back. The 3 large connectors are released by pressing tabs on either side and then pulling back on the cover. The connector on the bottom is a simple connector that only requires that the tab be pressed and then pulled straight out. The two connectors on the back have a lever that needs to be puled or pushed depending on the orientation and this will release the connector. To reinstall the connectors on the back of the CJB the lever must be fully locked in the released position, if it is loose or in the locked position the connector will not fully seat.


Explanation of the leak that puts water in the floorboard of the LR3 and Range Rover Sport: The forward sunroof drain tube goes from the front corner down the a pillar and then exits the Land Rover behind the front fender. There is a plastic nipple where the drain tube exists the vehicle, the drain tube has a rubber nipple that over time will disintegrate and then the drain tube will direct water into the interior of the Land Rover.

Two Sunroof Drain Repair Options

  1. Replace the entire drain tube. This requires buying a new drain tube for your exact vehicle, either the LR3 or the Range Rover Sport: This repair will require that you remove several headliner components like sun visors and handles so you can access the bottom of the sunroof where the drain tube attaches, then you must remove the a pillar, kick panel and lower dash components, glove box and CJB. After all this is done, you will then need to remover the old drain tube and then install the new drain tube.
  2. Repair the drain tube nipple. This is the repair that I explain in the video. With this repair you only replace the end of the drain tube by splicing on a new nipple. You will need to buy a new drain tube, this can be for any model that uses the exact type of drain tube nipple: and a 12mm straight push to connect union: This repair will only require that you remove the glove box, lower dash components and the CJB. When you have removed those parts you will then cut off the end of the old tube and splice on a new end with the new nipple.


One thought on “LR3 CJB Removal and Sunroof Drain Repair

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  1. chelsea 8 months ago

    On the back of the CJB box, there is an orange and green connector, which one goes on the left and which goes on the right?