Jaguar XJ6 Series 3 Window Switch, Windows Not Working
When every window on a Series 3 stops at once, check the small master switch on the centre console first — it is easily knocked off. After that the usual culprits are tarnished switch contacts, the window lift relay, or one side's thermal breaker; a single slow window points to the door wiring, the motor or dry channels.
How bad is it · Safe to drive
Safe to drive — but a window stuck down leaves the car open
A dead window doesn't affect how the car drives. A window stuck open lets in rain and thieves, so get it closed before parking outside.
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 console master switch is off or dirty
A small rocker on the centre console, beside the window switches, cuts power to every window and the sunroof. It is easily knocked off by a knee or a hand and mistaken for a sunroof or cruise switch. Dirty contacts inside it do the same.
Every window stops at once, often with the sunroof, and there is no blown fuse.
Flip the master switch and try again. If nothing changes, lift out the cubby lid and the sloping switch panel, unclip the two-wire switch and bridge its wires for a moment.
Flip it back to on. A dead switch can be opened at the pivot, its contact cleaned, lightly greased and bench-tested; a new one is C38637. It is a plain on/off rocker, so it fits either way round.
Worn or tarnished window switch contacts
The rear switches take their power through contacts in the front console switches, which close only when the front switch is at rest. A worn front switch can stop a rear window that tests fine on its own. A tarnished contact can still show 12 V yet pass too little current to move the glass.
A window that works one way only, goes lazy, or answers one switch but not the other; a rear window that won't go up from either switch.
Unplug both motor wires and put a test lamp from each to earth in every switch position. Lamp on both wires in one position: the switch is at fault. Lamp on neither: the power is lost between switch and motor. Swap switches between windows with care — a crossed lead can make a second fault.
Dismantle the switches over a towel, sand the moving contacts, polish the copper ones, clean with contact cleaner and add a little dielectric grease. Turning a one-way switch round gets the glass up for now; replace it to make it last.
The window lift relay
One relay feeds every window motor and the sunroof, and its supply wires carry no fuse. On LHD cars it sits on the passenger side, by the glovebox, not where some manuals put it. It runs warm in normal use.
All windows and the sunroof dead together, the master switch is on, and the relay does not click when the ignition is turned on.
Find the right relay before testing — swapping the wrong ones proves nothing. Feel or listen for the click with the ignition on, then try a known-good relay of the same type.
A good relay. The original is a black Lucas DAC1027, the same type used for the horn and load relays, so one can be borrowed to test; a standard 30/85/86/87 relay can replace it.
Wiring in the door rubber boot and the door connectors
The window wires bend every time the door opens and wear through inside the rubber boot between door and pillar. Corroded connectors in the door and a dirty motor earth add resistance until the motor stops.
Two windows on opposite sides dead while the others work, or a window that comes and goes; the switch works when fed from another circuit.
Open the boot and look for chafed or broken insulation. Clean the plugs in the door and the motor earth to bright metal.
Repair the worn wires — solder and heat-shrink lasts longer than tape. Clean connectors and earths; some motors need an extra earth strap where their mounting isolates them from the body.
A window motor that slowed and then stopped
A motor that labours against a stiff mechanism gets very hot. Compound inside can melt onto the commutator and stop it dead. A thermal cut-out in the motor also stops it until it cools.
The window was slow for a while before it stopped; the motor won't run even on direct 12 V.
Take the door card off, unplug the motor and feed it from the battery with jumper leads, both ways round. If it runs, the fault is upstream; if not, take it out and open it.
Soften the deposit with a heat gun, scrape and clean the commutator, check the brushes slide freely and put a drop of oil on the bearings. Free the glass and the lift mechanism before refitting, or it will stall again.
A thermal circuit breaker — one side of the car dead
There is no fuse for the windows: the left and right windows each go through a self-resetting thermal breaker. After years of tripping, one can stop closing again, leaving every window on that side dead.
Front and rear windows on one side stop together while the other side works.
The breakers are small black boxes with two wires, behind the kick panel below the glovebox. As a quick test, bridge a suspect breaker with a 20 A blade fuse across its clips. Don't swap breaker wiring between sides — that can make the good side fail too.
Worth trying: a new breaker. A stuck one can sometimes be revived by gently resetting its bimetal strip.
Dry glass channels and old regulator grease
Hardened grease on the regulator and dry rubber channels make the motor work far harder than it should. That load slows the glass and, over time, overheats the motor.
A slow, noisy window that speeds up when helped by hand.
With the door card off, look at the regulator grease and run the glass by hand where you can.
Worth trying: clean off the old grease, re-lubricate the regulator, and spray silicone or a rubber protectant into the channels. Don't force the glass.
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.
Flip the console master switch
The small rocker beside the window switches. If every window and the sunroof are dead, start here.
freeNote which windows have stopped
All of them: the master switch or the relay. One whole side: that side's breaker. One window, or two on opposite sides: the switch, the door wiring or the motor.
freeListen for the window relay
On the glovebox side on LHD cars. No click with the ignition on: try a known-good relay of the same type.
freeBridge a suspect breaker
Behind the kick panel below the glovebox. As a test only — don't leave it bridged.
a 20 A fuseTest lamp at the motor wires
Both motor wires unplugged, each to earth, in each switch position. It tells a switch fault from lost power.
a test lampRun the motor on jumper leads
Straight from the battery, both ways round. A motor that runs clears itself; one that doesn't comes out.
jumper leadsClean the switches and the door wiring
Strip and clean every switch, then check the wires in the door boot and the motor earth.
contact cleanerFree and lubricate the glass
Before refitting a motor, or a sticking mechanism will stall it again.
silicone sprayWhat it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar XJ6 Series 3 Power Antenna Broken or StuckThe other small motor that tires with age; the same direct 12 V test applies.
- XJ6 Series 3 fuse boxesWhere the fuse panels and relays sit on the 1987 layout.
- Jaguar XJ6 Series 3 Central Locking Not WorkingCentral locking on the same doors: fuse, driver's door control unit, seized linkages.
- 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.