After deciding to swap out my rotary switch in an ongoing attempt to cure the intermittent no start and failsafe mode, I just had to find out what that thing looks like inside that makes it worth so much money if purchased new (I bought used). what I found was a pretty cheaply made switch that no-one else makes. huummmm.
One thing that quickly became obvious is just how important a proper select cable adjustment is to not only proper operation, but to the longevity of the switch contacts. there are actually just two three gang switches inside this thing, which are positioned at approximately 10 and 2 o-clock in the first two photos. they are identified by the three silver "plungers" that contact the yellow plastic wheel. the wheel has a rather complex set of indentations in it that the plungers can drop into as it's rotated, which allows for a multitude of switching combinations. the switch contacts are simple brass strips with tungsten tips. the thing is, they are directly operated by the plunger riding against the wheel, so if the wheel is even slightly out of sinc, the contacts may not fully close, which could cause arcing and burning of the contacts (as mine show evidence of).
We're getting ready to go on vacation soon, but perhaps when I return I'll have time to more fully investigate a procedure to bench test this thing. it's not as simple as it may first appear. I've also noted that the widely available wiring schematic for these things shows 7 wires coming out of it, when in fact they have nine. then to further confuse things, it's rather unclear what color wire they are referring to on that schematic. is G green or gray (there is one of each) I'm guessing N stands for neutral, but what does S stand for? and how about RB (all wires are just one color) it must be another one of those metric things
anyway… I found it an interesting study so far, so perhaps you will also.

Russ

 

after 30 years rewiring/staring at electronics I am at a loss... RB for a single color wire? G would be Green, S would be Slate (Gray). If you have identified the remaining 6 wires, whatever is left would be RB. I'd be interested to hear what you come up with.

 

Betcha RB is really a faded pink with a totally faded out blue stripe.

 

red/blue?

 

Hi.


Here are the wire colour codes:

 

ahh, vindication. I still see nothing for RB in a single color wire. Look closely... maybe it's red/black.

 

The colours shown in the JTIS schema should relate to the car's external wiring rather than necessarily what the switch manufacturer uses internally, hence the apparent mismatch. (Internal colour coding is irrelevant as far as most end-users are concerned as they won't ever look inside or try to repair it). JTIS isn't 100% accurate, mind..

Do the colours on the switch loom match the 'Jaguar' colours on the other half of the connector?

I can only find 7 connections in any of the 1997-2004 MY diagrams, which implies that the switch isn't specific to the XK8.

Wonder what the unused pair does?

Mike

 

100% certain there are NO multi colored wires coming out of the switch. I had previously stripped the protective cover off the old switch loom and checked the wires very carefully. I did play with the thing for a few minutes again today, and have come to the conclusion (99% certain) that RB is the pink wire. the blue and red wires are switched to one-another, and are also the ones not shown on the switch schematic. no idea why they are there. maybe another switch application?
Question: should one be able to start an XK8 by placing the shifter in neutral? I was under the impression that you could, but I'm not seeing that possibility by inspecting the switch.

Russ

 

I have indeed started my XK8 in neutral.