XJ40 Gear selector information

Hi All,
I am using an XJ40 selector in a project and I know Diddly Squat about how it works electrically. The collection of cables in the photo are for illuminating gear position I guess? Or are they switches? Does anyone have a circuit diagram. I would like to make it work, so I need enlightening (no pun intended). Thanks for any help.

Hi: illumination AND start inhibit.

They are indeed switches …

Hi Larry, I’m well out my depth with the logic side of electronics, I was hoping for some switches in the Gear Position Indicator Module, the circuit diagram shows just LED, no switches. My gearbox also has no electronic control, although I will be replacing it with an ZF4HP22EH later.

The circuit diagram for the 1991my is different to my GPI module, it has a 1991 sticker on it. If I could find a circuit diagram that was the same as mine it would help.

Paul …

What is the project you’re using the XJ40 gear selector assembly for ?

If it’s something other than replacing it in an XJ40 then it’s just a matter of taking a multi meter and figuring out what readings you’re getting on each wire in each gear position.

The ZF4hp22 transmission is completely mechanical/hydraulic, no electrics involved. Also my understanding is that the ZF4hp22EH is the same transmission modified for 4 wheel drive.

So what do the wires do … illumination of course, audio warning, start inhibit, gear position display on dash, reverse signal, are among the functions that come to mind.


In principle that connector is for the lights and inhibitor. That 22 gearbox is operated by a mechanical cable linkage, and 8ndeed (edit) position in the dashboard.

Thank you for your replies, all appreciated.
The gearbox is going into a Triumph, so none of the Jag electronics will be used. I was hoping that I could use the GPI module to send gear position to the ECU that I will be using. Since then I’ve learnt that I should have had a rotary switch on the gearbox. I can’t retrofit one as it wouldn’t fit within the existing chassis, I can get over that tho. I will at least use the illumination side of the module hopefully.
The 22/24EH was used in Landrovers, but also in BMW’s too.

Mike pointed me to the JagRepair .com. The circuit diagrams are really useful.
Jaguar XJ40 1989my GPI Module