Poor idle, AC issues, probably vacuum problems (1982 XJ6)

Which one out of these two pics would be the hose your talking about

Neither. These are water. In the first picture there is a rubber line hanging down loosely. This either powers the heater valve (the die cast valve between the hoses you’re touching) or is the correct one and needs to connect to manifold via an one way valve.

There is three such hoses; one goes to the reservoir, one comes from the manifold and one closes the heater valve. Your heater valve is not original so someone did things in the area.

Locate the vacuum reservoir, Josiah - a round tin (usually black) fixed to the side of the engine compartment, usually near the brake servo. The reservoir has one vacuum line - which is the test point. And do get a vacuum gauge - it cost peanuts and is an essential piece of kit! Without it; vacuum issues cannot be identified or discussed…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

Hello it seems like my radiator is not plugged into anything ?!?

What’s does this cable even do ? What does it control ? Temperature gauge is working normally ? Is it safe to drive ?

Here is another random cable ? Was this the one that was plugged into the radiator? Did the connection pins just break off ? Or is this a completely different thing

That plug looks like ancillary fan. Maybe.

If that’s green and red it’s left hand flashers.

Otherwise, have a look here… A thank you to Jaguar Forums.

Firstly the basics- What The Colours Mean:
BROWN is for direct, unswitched, unfused supply from the battery. Seen on wires to alternators, dynamos, control boxes and ignition switches etc. Always live and often carrying heavy current.

YELLOW sometimes used as an alternative to brown on older cars. Also used on solenoids and overdrive switches.

PURPLE Direct, unswitched but fused supply from the battery. On older cars with no purple wires, brown wires with a secondary tracer colour are used.

WHITE Unfused supply from the ignition switch.

GREEN Fused supply switched via the ignition switch. Used for things like the wiper motor, indicators and brake lights which only work when the ignition is on.

BLUE The main colour for front lights- headlamps and spotlamps.

RED The main colour for rear and side lights.

BLACK Usual colour for wires from components to earth points on the body.

These refer to the main colour of the wire. The second tracer colour which is on many wires is the thinner line and is used to identify the wire. There is a certain amount of logic to them too as you will see.

Below is the colour code table for BS-AU7a which was amended in the 'eighties so there will be a few variations on our '50s to '70s cars…

Main colour is given first , tracer second

Black All earth connections
Black/ Brown Tachometer generator to tachometer
Black/ Blue Tachometer generator to tachometer
Black/ Red Electric or electronic speedometer to sensor
Black/ Purple Temperature switch to warning light
Black/ Green Relay to radiator fan motor
Black/ Light Green Vacuum brake switch or brake differential pressure valve to warning light and/or buzzer
Black/ White Brake fluid level warning light to switch and handbrake switch, or radio to speakers
Black/ Yellow Electric speedometer
Black/ Orange Radiator fan motor to thermal switch

Blue Lighting switch (head) to dip switch
Blue/ Brown Headlamp relay to headlamp fuse
Blue/ Red Dip switch to headlamp dip beam fuse. Fuse to right-hand dip headlamp
Blue/ Light green Headlamp wiper motor to headlamp wash pump motor
Blue/ White a) Dip switch to headlamp main beam fuse
b) Headlamp flasher to main beam fuse
c) Dip switch main beam warning light
d) Dip switch to long-range driving light switch
Blue/ Yellow Long-range driving light switch to lamp
Blue/ Black Fuse to right-hand main headlamp
Blue/ Pink Fuse to left-hand dip headlamp
Blue/ Slate Headlamp main beam fuse to left-hand headlamp or inboard headlamps when independently fused
Blue/ Orange Fuse to right-hand dip headlamp

Brown Main battery lead
Brown/ Blue Control box (compensated voltage control only) to ignition switch and lighting switch (feed)
Brown/ Red Compression ignition starting aid to switch. Main battery feed to double pole ignition switch
Brown/ Purple Alternator regulator feed
Brown/ Green Dynamo ‘F’ to control box ‘F’ Alternator field ‘F’ to control box ‘F’
Brown/ White Ammeter to control box. Ammeter to main alternator terminal
Brown/ Yellow Alternator to ‘no charge’ warning light
Brown/ Black Alternator battery sensing lead
Brown/ Slate Starter relay contact to starter solenoid
Brown/ Orange Fuel shut-off (diesel stop)

Green Accessories fused via ignition switch
Green/Brown Switch to reverse lamp
Green/ Blue Water temperature gauge to temperature unit
Green/ Red Direction indicator switch to left-hand flasher lamps

Green/ Purple Stop lamp switch to stop lamps, or stop lamp switch to lamp failure unit

Green/ Light green Hazard flasher unit to hazard pilot lamp or lamp failure unit to stop lamp bulbs
Green/ White Direction indicator switch to right hand flasher lamps
Green/ Yellow Heater motor to switch single speed (or to ‘slow’ on two- or three-speed motor)
Green/ Black Fuel gauge to fuel tank unit or changeover switch or voltage stabilizer to tank units
Green/ Pink Fuse to flasher unit
Green/ Slate a) Heater motor to switch (‘fast’ on two- or three-speed motor)
b) Coolant level unit to warning light
Green/ Orange Low fuel level switch to warning light
Light green Instrument voltage stabilizer to instruments
Light green/ Brown Flasher switch to flasher unit
Light green/ Blue a) Flasher switch to left-hand flasher warning light
b) Coolant level sensor to control unit
c) Test switch to coolant level control unit

Light green/ Red Fuel tank changeover switch to right-hand tank unit or
entry and exit door closed switch to door actuator
Light green/ Purple Flasher unit to flasher warning light

Light green/ Green Start inhibitor relay to change speed switch; or switch
to heater blower motor second speed on three-speed unit
Light green/ White Low air pressure switch to buzzer and warning light
Flasher switch to right-hand warning light; or
Light green/ Yellow differential lock switch to differential lock warning light
Light green /Black Front screen jet switch to screen jet motor

Light green /Slate Fuel tank changeover switch to left-hand tank unit; or entry and exit door open switch to door actuator

Light green/ Orange Rear window wash switch to wash pump; or cab lock-down switch to warning light

Orange Wiper circuits fused via ignition switch
Orange/ Blue Switch to front screen wiper motor first speed timer or intermittent unit
Orange/ Green Switch to front screen wiper motor second speed
Orange/ Black Switch to front screen wiper motor parking circuit, timer or intermittent unit
Orange/ Purple Timer or intermittent unit to motor parking circuit
Orange/ White Timer or intermittent unit to motor parking circuit
Orange/ Yellow Switch to headlamp or rear window wiper motor feed, timer or relay coil
Orange/Light green Switch to headlamp or rear window wiper motor parking circuit timer or relay coil
Orange/ Pink Timer or relay to headlamp or rear window wiper motor feed
Orange/ Slate Timer or relay to headlamp or rear window wiper motor parking circuit

Purple Accessories fed direct from battery via fuse
Purple/ Brown Horn fuse to horn relay when horn is fused separately
Purple/ Blue Fuse to heated rear window relay or switch and warning light
Purple/ Red Switches to map light, under bonnet light, glove box light and boot lamp when fed direct from battery fuse
Purple/ Green Fuse to hazard flasher
Purple/ Light green Fuse to relay for screen demist
Purple/ White Interior lights to switch (subsidiary circuit door safety lights to switch)
Purple/ Yellow Horn to horn relay
Purple/ Black Horn to horn relay to horn push
Purple/ Pink Rear heated window to switch or relay
Purple/ Slate Aerial lift motor to switch up
Purple/ Orange Aerial lift motor to switch down

Red Main feed to all circuits mastered by sidelamp switch
Red/ Brown Rear fog guard switch to lamps
Red/ Blue Front fog lamp fuse to fog lamp switch
Red/ Purple Switches to map light, under bonnet light, glove box light and boot lamp when sidelamp circuit fed
Red/ Green Bulb failure unit to right-hand-side and rear lamps
Red/ White a) Sidelamp fuse to right-hand side and rear lamps
b) Sidelamp fuse to panel light rheostat
c) Fuse to panel light switch or rheostat
d) Fuse to fibre optic source
Red / Yellow Fog lamp switch to fog lamp or front fog fuse to fog lamps
Red/ Black Left-hand, sidelamp fuse to side and tail lamps and number plate illumination
Red/ Pink Sidelamp fuse to lighting relay
Red/ Slate Lamp failure unit to left-hand side and tail lamps
Red/ Orange Fusebox to rear fog guard switch
Red/ Slate Window lift main lead

White Ignition switch or starter solenoid to ballast resistor

White/ Brown Oil pressure switch to warning light or gauge, or starter relay to oil pressure switch. Choke switch to choke solenoid (unfused) and/or choke to
White/ Blue switch to warning light, or electronic ignition distributor to drive resistor. Starter switch to starter solenoid or inhibitor switch
White/ Red or starter relay or ignition (start position) to bulb failure unit
White/ Purple Fuel pump no 1 or right-hand to changeover switch
White/ Green Fuel pump no 2 or left-hand to changeover switch. Start switch to starter interlock or oil pressure switch
White/ Light green to fuel pump or start inhibitor switch to starter relay or solenoid
White/ Yellow Ballast resistor to coil or starter solenoid to coil. Ignition coil contact breaker to distributor contact
White/ Black breaker, or distributor side of coil to voltage impulse tachometer
White/ Pink Ignition switch to radio fuse
White/ Slate Current tachometer to ignition coil
White/ Orange Hazard warning lead to switch
White/Yellow a) Overdrive
b) Petrol injection
c) Door locks
d) Gear selector switch to start

Pink/ white Ballast terminal to ignition distributor


Don has given a comprehensive outline of original Jaguar wire colors, Josiah - very helpful. Two ways to proceed; locating loose wires with corresponding colors - and/or finding out what is not working, and use wiring diagrams to find appropriate wire colors…

The two wires with a connector is probably for an aux electric fan, if fitted. In which case there should be a thermal switch screwed in at the side of the radiator - with a corresponding connector. Though the connector you have may connect to relevant relays or possibly to the fan motor itself…

Finding a home for loose wires is seldom straight forward. In some cases a PO may have willfully disconnected wires to counter a fault, or removed items - or simply found other ways of connecting some items. Adding that Jaguar used the same harness for all options - leaving wires for options not fitted unconnected…

But while you are looking; insulate the bare ends of the loose wires…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

Tape it off and leave it that way. You can worry about it when you understand the car. Buy the green workshop manual and you will have most of the information you need.

5 threads about the same car and related issues have been collected in this thread now.

Hi Josiah

You seem to have a number of problems with the car and I assume it is new to you - perhaps you only just bought it. You say elsewhere that you are new to cars and learning as you go along and I encourage you to to pursue that aim. However, the apparent condition of the car suggests that it has not received the best maintenance in the past and there may be other (perhaps more serious) issues yet to discover.

Perhaps you might consider taking it to a reputable Jaguar shop and have them look over it thoroughly to give you direct advice on its complete overall condition. At least then you will have a starting point from which to make decisions and prioritise work.

Good luck.


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