Gents,

I am curious if anyone has fitted an aftermarket Cruise to their XJS, I have an 1981 model and it is lacking Cruise.

Suggestions on brand or best route to go?

Thanks.

 

More than likely waaaaay out of date.

25+ years ago I fitted a Command Cruise to my '85. The factory thing died spectacularly,

Magnets on the prop shaft, bellow outside the engine bay, alongside the spare Vac Tank, cable attached to the OE cable with home made joiner plate.

2020

I am told there are electric units, using the transducer pulse in the trans, and are "WiFi, or is it Bluetooth" communications, beyond my grey matter now.

The fact you have nothing, may be a tad more involved with the cable pull set up. Maybe 6 more beers for that one.

 

I still have one of those units. Used it on three different company cars in the early/mid 90's
Also known as a Zemco ZT1 from memory.

Brilliant system. I even worked out that if you put a switch on the clutch pedal and wired that switch in series to one of the two "safety" wires that connected either side of the brake light swich you had a $2 upgrade that cut the cruise when the clutch pedal was depressed. Far simpler than the somewhat costly manual trans upgrade module.

An 81 XJ-S probably still has a speedo cable so it's probably the magnets on the prop shaft for the speed control due to no transducer.

 

Jaguar used AE Econocruise which basically was an aftermarket system. AE would install it on any car you brought them. Anyway, I bring it up because I feel the best thing for you to do is write David Boger at everydayXJ.Com and just get the parts you need used. -John

 

I have the female speed control fitted in my xkr. Upon hearing the supercharger on our last trip out she told me,
“ you know it’s not allowed to make that noise when I’m in the car” . Lol

 

I've used aftermarket cruise control on another car, & can see no reason why it couldn't work on the xjs. The only thing you need really is a speed pulse signal - does this exist on the xjs or is the Speedo mechanical?

 

Andrew
Apart from very early HEs, to about 1982 or 3, the speedo thereafter is activated by pulses from the gearbox, in the case of the GM400 cars, at 8000 pulses per mile (either that or 7000, I forget).
I have found that aftermarket cruise systems that are now available only work with fly by wire throttle systems, not with mechanical (ie cable operated) ones. If you find anything different, please share it. The OEM system clutters up the V too much for my liking.

 

Greg,
The kit I used was very similar to this one, & was purchased from the same company around 7 years ago, but it was around £230 & used a vacuum operated additional throttle cable like the XJS, rather than this electric motor actuator:
https://www.conrad-anderson.co.uk/pr...iversalGC55Kit

The control box was identical, but the kit I had was the most basic, so came with this control switch:
https://www.conrad-anderson.co.uk/pr...d-modules/gc01

If you contact them & ask if they still do the basic vacuum operated cruise control universal kit, I'm sure they'l let you know. I think it was branded 'JohnGold' & was a brand from the Netherlands/Belgium - I've got the box buried somewhere with the exact model info.

The only electronic inputs were for the vehicle speed signal, & brake/clutch cutoff switches IIRC. It was fairly simple to program so it smoothly transitioned when engaged, & each press of the +- switch incremented your speed +- 1mph etc.

EDIT
Scroll down to the bottom if this page & you can see the vacuum actuator; looks like the kit is the GC50:
http://www.autotec.ie/Gold_Cruise.html

 

brilliant, thanks Andrew. The Conrad one is too dear for me, so I will call Autotec guys and see.

 

Give Conrad a call also, I'm sure if the cheaper basic vacuum kit is still available they will be able to supply it. Agree that the price on there for the one linked is ridiculous!

 

If you Google "Audiovox Cruise Control Kit" or "Rostra Cruise control Kit" you'll see many choices

Cheers
DD