Greetings,
I'm helping a friend wire a frame off restoration on a '58 xk150. I wasn't around for the disassembly. We have a new wiring harness installed and mostly hooked up. BUT I've found three different diagrams for the overdrive circuit. 1) 4 terminal single relay, 2) two 4 terminal relays and throttle switch, 3) 5 terminal relay with throttle switch. I have a 5 terminal relay that was removed from the car, and no sign of a throttle switch. I can't even tell where a throttle switch might have been mounted, besides near linkage.
My relay is marked C1,C2,C4,W1,W2. Seems like the harness has plenty of wires for any overdrive circuit options. How do I make it work???
Thanks, Al

 

It would be imortant to state which electrical drawings you are using (bottom right of the drawing) and what the chassis number is. Sounds like you are using at least an early XK140 drawing in your efforts.

 

I don't have the VIN with me at the moment. Supposedly 1958 (early) These are the only overdrive diagrams available in the books we have,,,, 1st is out of a Clymers workshop manual, 2nd is from "Jaguar XK 150 explored" hard cover book, 3rd is from XK's Unlimited.

 

Number is S831625DN

 

Use the last two drawings. The throttle switch would have been mounted on the front carb. The switch is much like the later hand brake switch but with different terminal fittings. It mounts on a special little bracket. Perhaps it has been removed but the wires to it would be shorted together.

 

Thanks!!