Transfer Gearbox - Shifting Triggers Door Locks
Bulletin: P93/37-001Section: Product
Date: 2/18/93
Model: Range Rover
Applicable to: USA/CND
Subject:
SERVICE ACTION H812 - 1993 RANGE ROVER TRANSFER GEARBOX INTERLOCK SYSTEM
Movement of the automatic transmission shift lever from Park into gear or vice-versa triggers the transfer gearbox interlock relay. A momentary arcing or voltage surge across the relay contacts due to current flow occurs whenever the shift lever passes through the neutral position. This voltage spike can intermittently influence the central door lock system control unit and cause it to:
^ Unlock the vehicle's doors when the shift lever is moved from Park into gear
^ "time out" the door lock system for 20 to 50 seconds giving the appearance of a door lock or security system failure.
The voltage surge may also cause popping noises in the audio speakers and subwoofer.
Beginning with VIN ...PA631649 the Factory incorporated a diode into the transfer gearbox interlook harness to prevent the voltage surge from occurring. Starting with VIN ... PA630935, our Ports began installing a service type anti-arc harness which serves the same purpose.
In the interest of customer satisfaction and vehicle uniformity, all 1993 vehicles in service or dealer stock but not Factory or Port updated will require the installation of an anti-arc harness at the next service opportunity. No customer notification will be made.
AFFECTED VEHICLES
^ All 1993 Range Rover vehicles from VIN ... PA624756 to VIN ... PA630935.
NOTE:
You may find a few vehicles within the above VIN range which have already been dealer updated on instructions from our Techline or Field Engineer. They, like the later Port updated vehicles, will have a visible diode harness connected between terminal 87 of the interlock relay and ground and require no action.
PARTS INFORMATION
In order to perform this service action, you will need one (1) anti-arc harness assembly, Part No. RTC7770 per vehicle. Please order directly through your parts department.
WORK PROCEDURE
^ Remove the cubby box liner and locate the yellow transfer gearbox interlock relay which is clipped next to a green relay on the right side of the console.
^ Pull the relay and base off it's clip as a unit.
^ Locate the slate/black (SB) wire connected to relay terminal 87. Cut and strip back its insulation as shown in the illustration.
^ Using the illustration as a guide secure the terminal block from kit RTC7770 onto the SB wires at one end and the supplied anti-arc harness wire on the other. Secure the screws.
^ Loosen the right hand console to floor bolt and slip the eyelet of the anti-arc harness under the bolt's washer. Re-tighten.
^ Test by switching on the ignition, placing your foot on the brake and moving the shift lever from park through all gears (and neutral) several times. The relay should operate, but no arcing should be visible through the relay case.
^ Reinstall the relay into the clip and replace the cubby box liner in the console.
WARRANTY INFORMATION
Complete warranty claims as follows:
Service Type: WW
Repair Code: H812
Labor Operation: 999980 .25 hrs.