I have a 1962 Mk2 Auto, the speedhold sensor has never worked and I’d like to test/replace it: does anyone know where the speedhold sensor is located on the car?
thanks

 

Howiez it is not a sensor but an electric SOL. that when engaged locks the trans in second gear. Test the electricals first. If your transmission shifts through the range it is either the switch--wiring or the SOL.

 

Many thanks, could you let me know where it is situated /what it looks like so I can run a few tests on both the SOL and wiring to it? Regards

 

it is located on the passenger side of the transmission, in the DG250 transmission at least. Also this is in Left Hand Drive cars.

if you raise the front of the passenger side transmission tunnel capeting, there is a removable panel through which you can access the speed hold solenoid, or just raise the car and you can find it.

There are two wires connecting to it: One is green, one is black.

 

Thanks

 

The feed to the switch is from fuse 4 and is the green wire to the switch, there should then be a yellow/red wire to the solenoid and then to earth.

I think that in-line fuses were added in 1964, but could be retro fitted, there is a service bulletin for this I think.

If it was added to yours it should be behind the fascia below the speed hold switch. so if you have no feed, check for an in-line fuse.

 

Is the facia simple to remove to get access to the switch please

 

It's not too difficult, do you have a workshop manual, or do you need an explanation, if you PM me I can give you a link to the info.

 

you can get to the switch by looking up from below the corner of the dash?, at least in my S type you can. The two wires are screwed to the switch, with two flat head screws.

Jon, yes, my switch has an online fuse, located very close to the switch in one of the two wires, very easy to replace in my S type.

 

Many thanks, I'll have a look very shortly, it would be great to get the speedhold back into operation.

 

yeahh, just don't forget to turn it "OUT" (or OFF"). I had this problem with leaving it "IN" (or ON"), and forgetting to turn it off at highway speed!!!. So Mike Eck (jaguarclock.com) made me an amber LED to let me know the darned thing was ON.

 

on the subject of a Warning Light for the Speed Hold, Jaguar should have put an indicator light in the "2" at the shifter quadrant in automatic cars. They didn't. How do you like that?

 

Well, I’ve managed to get to the speedhold switch and surprise, there’s not a live feed to it; neither does there appear to be an inline fuse, the power lead traces back behind the dials and I think then feeds into the main wiring loom. I suppose I could try a new feed for the switch. I can’t quite work out why it’s not receiving any power feed: I only seem to have 2 fuses feeding the car located in the engine bay and both seem intact

 

somebody butchered the wiring.

 

Have you dropped the centre dash panel to see if there is anything amiss there?

 

The main feed should go straight back to the fuse check the connections at the fuse, see if anything has come adrift. Check for continuity from the feed to the fuse, take the wires out from the fuse position and ensure all terminations are clean.

Do you have a workshop manual ?

What is the Chassis No of your car ?

If you need the wiring diagrams etc. PM me and I can send them to you.

 

Thanks for the responses, all very useful.
I agree, the wiring to the switch has been changed at some point. I’ve tried tracing it back but it disappears behind the dials and unless I remove these dials, I won’t be able to find my way back along this feed.
I’ve also pulled back the central dials, but can’t see any trace of the wire here. Neither can I establish where the wire connects to the main fuse as the wires don’t appear colour coded in the fuse area.
I have a workshop manual thanks and hopefully have established the correct colour codes for the wiring.
My current thoughts: to utilise a redundant wire beneath the dash, which is coded purple and black, being the old feed to the horn (there’s an aftermarket horn)and for safety, insert an inline fuse into this feed and then provide the speedhold switch with a new live feed and then see if 1. I have power to the solenoid and 2. Whether the speedhold then works!
Happy to update you soon

 

That sounds like a good plan, let us know how it goes.