Jaguar XJ6 Series 3 Won't Crank, Just a Click
On the Series 3 the key doesn't feed the starter — it pulls in a relay on the bulkhead, which needs the gearbox switch in Park or Neutral and power from the firewall posts. The relay, the feed and the battery are as often to blame as the starter, so I wouldn't buy a starter first. Two free tests — the lights and bridging the relay — tell you which half to look at.
How bad is it · Garage, carefully
Stranded rather than unsafe
Bridging the starter relay bypasses the gear interlock, so the car will crank in any gear — select Park or Neutral and set the handbrake first. A relay or post that has been arcing is a heat problem: replace it rather than keep cleaning it.
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 starter relay on the bulkhead
The key energises a relay next to the battery, which feeds the starter solenoid. Its contacts pit and burn with every start, and a push-on connector can work loose. A relay can even click and pass a bench test with the contact missing from one of its two poles.
A click from the bulkhead, nothing from the starter; a tap on the relay or a wiggle of its wiring gets it going for a while.
Park or Neutral, handbrake on: touch the heavy white/red wire from the relay to battery positive. If it cranks, the starter is fine — the relay or its control side isn't. Check every spade grips tightly.
A new relay — a DGSRB301, or a cheap generic Chrysler-type one — or squeeze a loose white/red connector tighter. A suspect relay that tests fine is worth opening: burnt or missing contacts show at once.
The battery feed: firewall posts, cables and terminals
The heavy positive cable from the boot battery runs to a firewall post that feeds the whole car. A dirty or loose joint shows voltage on a meter but can't pass starter current.
A single click, or the car totally dead even on a new battery or a jump; the solenoid chattering.
Battery disconnected first — the posts are always live. Clean cable ends and both posts to bright metal, tighten and grease. Test under load, not just with a voltmeter; a cable end that is warm straight after cranking is a bad joint. Rule this out before condemning the starter: build up from a healthy battery and sound cables with clean ends, then the relay and solenoid path.
Clean and tighten the posts and battery terminals; renew corroded positive cables.
The battery, even when it shows voltage
A battery with an internal break reads normal at rest and collapses the moment the starter asks for current.
Dead or a click while the posts show voltage; lights don't dim at all, or dim to nothing.
Try a known-good battery, or have yours load-tested. At rest a full battery reads about 12.6 V; 12.4 V is only about two-thirds charged.
A new battery.
The ignition switch
The electrical switch sits behind the steering lock. Its contacts wear — a heavy bunch of keys hastens it — and after a replacement it can come adrift from the lock.
No click and dash lights dead with the key on; or a key that turns with no resistance, especially after a new switch. Silence with no click at all, coming and going — it starts for hours, then fails again after standing.
Bridge the relay's white/yellow start wire to the brown battery feed: if it cranks, it's the switch. Check the switch is still locked to the barrel. A test lamp on the white/yellow wire at the relay, key held at START, shows whether the key feeds the relay at all. A click from the relay or solenoid means the switch is doing its job in that position.
A new switch, or push an adrift one back onto the lock.
The starter itself: solenoid contacts, brushes, armature
Solenoid contacts burn, brushes wear, armature joints come apart. A starter can pass a no-load bench run and still fail in the car.
Relay clicks and full voltage reaches the solenoid, but the starter barely turns; hot restarts sluggish; or a click now and then until a tap on the starter body brings it round — a dead spot. A single click and now and then a chatter, sometimes with the dash lights going out; bridging the relay gives one click and a fat spark at the lead, but no turn.
Relay bridged and good voltage at the heavy terminal, yet no turn — it's the starter. In Park, bridging the two big solenoid terminals with a heavy screwdriver tests the solenoid contacts: if it spins now, they're gone. Only a full-load test proves a starter. Switch the headlamps on and try again: if they dim hard, current reaches a starter that can't turn — worn, or an engine locked by fuel or seizure. It is worth jumping the motor and the solenoid separately.
A remanufactured or sound spare starter: a gear-reduction unit, or the original Lucas overhauled by an auto-electrician. If it grinds on engagement, check the ring gear for worn teeth. If the ignition switch was already weak, check it too — the two can fail together.
A replacement relay or rebuilt solenoid wired to the wrong terminal
Relays and rebuilt starters from different sources don't always match the original layout. On a Lucas 22RA the white/red starter wire belongs on C1 — C4 is a lighter secondary contact.
The trouble started straight after a new relay or a rebuilt starter went in.
At the relay: brown battery feed on C2, white/yellow from the key on W2, black/green to the inhibit switch on W1. On a rebuilt solenoid, try the feed on the other small spade.
Move the white/red wire to C1 — bridging C1 and C4 at the spades also works. A substitute relay needs a low-resistance coil, under about 20 ohms; one of 50–60 ohms is meant for continuous duty, not the starter.
The starter spacer missing
The Series 3 starter sits on a spacer about 1/8 in thick between it and the bellhousing, which sets how the pinion meets the ring gear. Left out, it gives slow, laboured cranking that no new starter cures.
Sluggish cranking that survived one or more starter swaps.
With the starter off, look for the spacer. Compare a replacement with the old one: pinion size, teeth and the distance from mounting face to pinion should match.
Refit the starter with its proper spacer.
The engine itself won't turn
After a long lay-up the pistons can rust to the bores. The starter gets full current but can't move the crank, so the pinion just clangs against the flywheel.
A clang from the starter, the battery voltage dropping hard and the cables warming, yet nothing turns. Typically after years of standing.
Plugs out, a spanner on the crank pulley nut, and try to turn the engine by hand. With the starter out, the ring gear can be levered round through the opening.
Penetrating oil or diesel in the bores, steady gentle torque on the crank, and patience; once it turns freely by hand, the starter spins it as normal.
The start inhibit switch on the gearbox
The relay earths only through a switch closed in Park or Neutral. With age its contacts or adjustment drift.
A click, fuel pump whining, no crank — intermittently or after a drive; it cranks if you wiggle the selector or press it firmly into Park.
Wiggle the lever with the key in START. At the relay, earth the black/green wire: if it cranks, it's the switch or its wiring. Remove the bridge once fixed — it lets the car crank in gear.
Worth trying: clean the switch contacts; earthing the inhibit wire is a stopgap only.
The engine earth strap
The starter returns current through the block, and the braided straps by the sump live in road dirt and water.
Slow cranking or a click with a good battery.
Clamp a jump lead from battery negative to the block. If it now cranks properly, the earth is the fault.
Worth trying: clean or replace the straps, or run a heavy extra cable to the block.
The small trigger wire or the heavy lead at the starter
The solenoid's small spade carries the signal from the relay, the heavy lead the current. The spade can shake off, and the heavy lead can break inside its boot while looking whole.
Dead silence from the starter after work under the bonnet or a lot of slamming, though bridging the relay at the bulkhead proves the starter good.
Battery disconnected, look at the small spade between the two big terminals on the solenoid. Peel back the boot on the heavy lead and look for broken strands or a corroded lug.
Worth trying: push the spade back on firmly, clean a corroded lug, renew a lead with broken strands.
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.
Park or Neutral, handbrake on — wiggle the selector
If it cranks while you wiggle, it's the inhibit switch.
freeWatch the lights as you turn the key
Nothing lights: battery connections or ignition switch. Lights die as you crank: battery or connections. No dimming at all: current isn't reaching the starter. Lights dimming hard with a click and no turn: the starter is getting current and can't use it.
freeClean battery terminals, firewall posts and earth strap
Battery disconnected first. A jump lead to the block tests the earth.
freeBridge the relay: white/red to battery positive
If it cranks, the starter is fine: relay, inhibit switch or ignition switch. With an intermittent fault, make sure the fault is still there at the moment you test — otherwise a bridge that cranks proves nothing.
freeLook at the wires on the starter
If the relay clicks but the starter stays silent: battery off, check the small spade on the solenoid and the heavy lead under its boot.
freeSwap the relay
A generic one works, wired to the diagram printed on it.
from about $10A known-good battery
Rule the battery out under load before the starter.
free to borrowTurn the engine by hand
Plugs out, a spanner on the crank pulley nut. If it won't move after a long lay-up, it's seized, not electrical.
freeOnly then the starter
A gear-reduction starter draws less current. Insist on a full-load test for anything rebuilt, and refit it with its spacer.
rebuild or a new unitWhat it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar XJ6 Series 3 Battery Drain, Flat After a WeekIf it clicks because the battery goes flat overnight, start there.
- Jaguar XJ6 Series 3 Won't Start, Cranks But Won't FireIf it turns over normally but won't fire, start there.
- XJ6 Series 3 fuse boxesThe fuse panels of the Series 3.
- 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.