Jaguar XJ6 Series 3 Central Locking Not Working
On a Series 3 dead central locking is most often a blown locking fuse, a sticky or failing control unit in the driver's door, or one door whose linkage has seized. I'd start free: work out whether the car has Lucas solenoids or Kiekert motors, check the fuse, then put a bulb on the driver's door pulse before buying any motors.
How bad is it · Safe to drive
Safe to drive; lock the doors by hand
Dead locking doesn't affect how the car drives. If motors keep failing one after another, pull the locking fuse until the driver's door unit is tested, or it will burn out the new ones too.
Which one applies to yours depends on your symptoms, your model year and what has already been done to it.
Likely causes, most common first
Read the check cost before the odds: a free check that rules a cause out beats a likely guess that costs money.
The central-locking fuse has blown
The locks have their own fuse, and the printed guides don't always show the right one. On a 1987-layout car it is fuse 17 on the auxiliary panel in the right footwell, shared with the door lights and mirrors; earlier cars may have an inline fuse near the panel on brown/blue wires.
Nothing happens from the key or the switch, on any door, and there is no click.
Pull the fuse and look, and clean its contacts. If the mirrors work, don't assume the locking fuse is good — on some cars it is a separate inline fuse.
A new fuse. If it has blown, check the driver's door control unit before trusting the repair: a unit that sends too long a pulse blows fuses and burns motors.
The driver's door control unit is dirty, off-centre or failing
On Kiekert cars there is no motor in the driver's door, only a control unit that the key rod trips. It sends a pulse of about one to two seconds to every other motor, reversing polarity to lock or unlock. If it sticks, it can keep power on until the motors burn out one after another.
All the other locks are dead or erratic together; or it clicks steadily without moving anything; or motors keep failing one by one.
Put a headlamp bulb, not a small test lamp, across the orange/green and orange/red wires and work the key. You want a short flash each way; a long or no flash points at the unit.
Re-centre its neutral position on the key lever. A sticky unit can come out on two bolts, be flushed with contact cleaner and refitted. Fit new motors only after the unit tests right, or they will burn out too.
A seized pivot or dry linkage in the door
The motor or solenoid can be perfectly healthy and still fail to move the latch. The pivot arm on the lock mounting plate rusts solid, and old hardened grease stiffens the rods.
One door, often a rear one, won't follow the others, while its motor or solenoid works on the bench.
With the door card off, work the rods and the pivot arm by hand. Anything that won't move freely is the fault.
Soak the pivot in penetrating oil, work it back and forth until it is free, then wipe it out. A badly rusted plate is best cleaned, painted and oiled properly. Cleaning and greasing the linkages alone often brings a dead lock back.
One door's lock motor or its plug
Each door has a Kiekert motor on two wires, orange/red and orange/green. A loose plug looks just like a dead motor, and age or a long pulse from the control unit burns the windings.
Only one door is dead. If it unlocks but won't lock, suspect adjustment; if it does nothing at all, suspect the motor.
The motor sits at the upper part of the door behind a bracket on 10 mm bolts. Unplug it and put 12 V across its two wires, then reverse them: it should drive one way, then the other. Nothing either way means it is dead.
Refit the motor with its plug firmly home — that alone can cure it. Otherwise a genuine or used Kiekert motor; aftermarket ones bolt to the brackets. Slide the bracket to set the travel and tighten the bolts well, or it slips.
The boot is meant to stay locked
From the factory the boot locks with the doors but won't unlock with them. On Kiekert cars the boot link sits in a long slot that wastes the unlock stroke; the boot motor itself runs both ways.
Every door locks and unlocks, and the boot locks with them but has to be opened with the key.
See what the boot linkage connects to: a round solenoid means Lucas, a flat square box means Kiekert.
On Kiekert cars a small bolt and nut through the slot, with a dab of locking compound, makes it unlock with the doors. On Lucas cars the boot solenoid's spare wire has to be run forward and joined to the door wiring instead.
Early cars: the lock or unlock relay
Cars up to about 1984–85 have Lucas solenoids, not Kiekert motors. The key switch fires one of two relays — one for lock, one for unlock — behind the footwell kick panels, though some early cars have them behind the rear seat.
It unlocks but won't lock, or the other way round, with no click at all.
The lock relay carries orange/green wires, the unlock relay orange/red; both share brown/blue power and a black earth. Confirm power on brown/blue with a test lamp, then briefly jump the trigger wire to it: the relay should click and the solenoids fire. Swapping the two relays is a quick test.
Worth trying: a new relay for the direction that doesn't work. If relays and solenoids all test fine, look at the switch and the thermal breakers.
The key cylinder no longer drives the lock
The key and the central locking are only loosely coupled. The cylinder's square end drives a small lever, and the tab between them can wear or break off, so the key turns but moves nothing.
The key feels rough, loose or stuck, but the inside tab still locks and unlocks the door normally.
Try the door/boot key instead of the ignition key, and lubricate the cylinder. Then take the door card off and unhook the cylinder's rod to see whether the cylinder or the latch is at fault.
Worth trying: lock lubricant and the right key. A broken drive tab means repairing or replacing the cylinder.
The order to check them in
The point of the order is money: each step either rules a cause out or makes the next one worth doing. Green is free, amber costs a little, red is the one to arrive at last.
Find out which system you have
Relays behind the footwell kick panels and a round solenoid on the boot link mean Lucas; a flat square box on the boot link means Kiekert. The faults and tests differ.
freeCheck the locking fuse
Fuse 17 on the auxiliary panel in the right footwell on a 1987-layout car; an inline fuse on brown/blue wires on some earlier ones. Clean the contacts. If it has blown, do the next step before relying on it.
a fuseTest the driver's door pulse
A headlamp bulb across orange/green and orange/red while someone turns the key. A short flash each way is right; a long one will burn motors.
freeDrive the other doors directly
Unplug the driver's kick-panel connector and put 12 V across orange/green and orange/red, then reverse. If every door moves both ways, the fault is in the driver's door.
freeFree the lagging door's linkage
Door card off — rear trims come off with the door shut. Work the pivot arm and rods, free anything stiff, oil it.
penetrating oilBench-test that door's motor
12 V across its two wires, then reversed. If it runs, refit it with the plug fully home; if not, replace it.
freeClean or re-centre the control unit
Two bolts inside the driver's door; a 1/4-inch ratchet helps. Flush it with contact cleaner and set its neutral position on the key lever.
freeEarly cars: test or swap the relays
Power on brown/blue first, then trigger each relay by hand. Swapping lock and unlock relays shows which one has failed.
a relayThe fuses named above — where they sit
The highlighted position is the one the procedure talks about. Pulling a fuse is a stop-gap, never a repair: check what the circuit feeds before you pull it.
We have no drawing of this box for this car — find them on the legend printed on the lid of the box itself.
What it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar XJ6 Series 3 Window Switch, Windows Not WorkingThe other door-mounted motors; the same door card has to come off.
- XJ6 Series 3 fuse boxesWhere fuse 17 sits on the auxiliary panel of the 1987 layout.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
Ratings, fuse numbers and torque figures vary by model year and market. Read the legend on your own car before pulling anything, and use the figures in the manual for your car, not the ones in a video.
Check your VIN: exactly which car you have and which bulletins apply to it.