Ignition Switch Removal


(Eric Capron) #21

The feed to F27 comes through one section of the ignition switch and that should not be there with the key out (or in with the ignition off). It looks like that power comes from the Rear Power Distribution Box and the main fuse supplying it is Fuse 31. If you put F27 back and pull F31 and the radio goes off it strongly suggests the power is coming through that section of the ignition switch.
You could prove this by unplugging FC18 on the ignition switch and seeing if there is continuity between pins 1 & 4 on the switch with the connect unplugged.


(Rob Reilly) #22

F31 in the passenger compartment is empty. My handbook says it is not used.

On F31 in the luggage compartment my handbook says it is also not used, but there is a fuse in it. I pulled it out and the radio and clock stopped. The door open chime has also stopped but I don’t know what I did to change that. When I put F31 back in the horns start tooting the theft alarm. This is with a door and the boot lid already open. I disconnect the battery and the horns stop, then when I reconnect the battery with a door open the horns are off, but when I open another door they start tooting.


(Eric Capron) #23

I suppose the alarm is armed and it’s responding to the removal of power to monitored modules. Putting the key in and starting the engine should shut the horns up.
Did you get a chance to check to see if there is any continuity between pins 1 and 4 on the switch? There shouldn’t be any with the key out but because the radio stopped when you pulled F31 it suggests there is a circuit there somehow. I think you already have the electrical guide?


(Rob Reilly) #24

Yes, I tried it again, connecting the battery, then opening the door triggered the alarm, but starting the engine shut the alarm off, and it did not alarm again. But the radio is still on.
Yes I have the electrical guide wiring diagram.
The pins on the switch are not numbered, but they are labeled inside; going clockwise is KEY, B+1, ACC3, STR, ACC1, IGN, ACC2, B+2.


Wire colors on the connector in the same order are red/white, red/green, pink/white, slate/black, yellow, green/black, pink/yellow, red/black.
I checked all the continuities on the new switch and didn’t find anything wrong. The KEY IN function is performed by a push pin in the center being pushed in by the tumbler extension shaft when the key is inserted in the tumbler. B+2 connects to KEY when this pin is pushed in.

Way below freezing out there so I’m staying in tonight.


(Eric Capron) #25

So it seems the functions relate to the switch pin numbers on diagram as follows:

Pin 1 B+1 R/G
Pin 2 ACC3 K/W
Pin 3 STR S/B
Pin 4 ACC1 Y
Pin 5 IGN G/B
Pin 6 ACC2 K/Y
Pin 7 B+2 R/B*
Pin 8 KEY R/W
*The diagram I have shows the B+2 wire as being R/O for NA vehicles not R/B but I have found other mistakes in diagrams.

The feed to the radio from Pin 4 (Y) also supplies the headlamp level adjustment and the Instrument Pack via two other fuses. The PATS part of the IP also gets the Key In signal from Pin 8 (R/W) and I suppose the chimes are because it sees conflicting information ie having a B+ supply without the Key In signal. Since there is clearly nothing wrong with the switch itself, I just can’t see how there are volts leaving Pin 4 when the key is out unless there is something wrong with the plug (unlikely) or something mechanical is causing those contacts to close when the switch is fitted in to the barrel.


(Rob Reilly) #26

Thanks Eric for continuing with me on this journey into the murky woods. :smile:
Today I tried pulling each relay from the rear distribution box, but none shut off the radio. Pulling fuse 31 in the boot shuts it off, and then reinstalling it starts the horn alarm.
I also noticed the remote fob locking/unlocking does not work, not sure if I mentioned that before.
I now see the pin numbers you refer to in the wiring diagrams.
On Figure 01.1, wire color RO at pin 7 becomes color RB lower down the page, and then changes to R, for no apparent reason. As you say, likely a mistake or two there.
Tomorrow I will check for closed contacts at Key and B+2 and a mechanical reason for it. The coil spring shown in my earlier pix is supposed to push the tumbler shaft out when the key is removed. It could be that the 3-in-1 sewing machine oil I put on it is too gummy at below freezing temperatures.


(Rob Reilly) #27

I think we’re onto something. With a cold cylinder I have variable continuity across KEY and B+2 with the key out. I guess it comes apart again.


(Rob Reilly) #28

Progress has been interrupted by snowstorms. :confounded:
I have determined that there is something wrong in the way the lock cylinder shaft interacts with the plastic switch. The shaft has a stroke of about 3/16" or 4mm from key out to key in, pushing in the KEY plunger in the switch. The lock cylinder does not pop out as it should when the key is removed. But I give it a hard tap and it pops out.
The switch operated separately shows continuity correctly in all positions. But when I put them together, I get incorrect and inconsistent continuities.
I also managed to shut off the alarm by connecting the switch and operating the key fob button, locking and unlocking.
The radio comes on immediately when I connect the battery, even if there is no ignition switch connected at all.
I can shut off the radio manually, and then the clock goes off after a few seconds as it normally did.


(Rob Reilly) #29

More mysteries.
With the ignition switch and key identity coil connected, but no key in the lock, or with no ignition switch or key identity coil connected at all…
I touch the battery ground cable to the terminal and I can hear and feel all 4 switched power relays in the rear distribution box operating.
According to page 1.2 and 1.5 of the wiring diagrams they are all connected to battery positive through fuses, and to the switched system power controls in the general electronic control module and the rear electronic control module.
They should not be operating then, without a key or ignition switch, should they?
There is a note on page 1.5 - “SCP Note: The switched system power relays are activated by the GECM or the RECM whenever messages are present on the SCP Network. After the ignition is switched off, the relays remain activated until all SCP messages are removed.
Does anyone have any idea what that means?
I found a list of 434 SCP messages in the appendix of the book.
Is there a way to read them on the car?


(Eric Capron) #30

Rob,
I wasn’t surprised that you could hear the four ignition controlled power relays switching when you connected the battery. The way S Type power distribution is configured, when you disconnect and reconnect the battery the system does a hard reset and GECM & RECM power those relays as they boot up.
To make certain, I went and tried it on my car and it does exactly the same.
You are probably aware that when you switch off the ignition the car goes to sleep in stages.In the process, SCP messages are sent from module to module. S Type makes heavy use of SCP messages in the body functions as you found out. (XJ of the same age only uses 140 SCP messages because it uses other network protocols). I have monitored the SCP bus at module connectors and I think you can do also do it at the diagnostic connector although I’ve never done it. To see the data you need an oscilloscope or you can use WDS with the VMM which is better because the software is designed to show the data and freeze it.
Although I’ve used WDS quite a bit I haven’t yet seen any option to decode individual SCP data words and the most I’ve been able to do so far is to establish that a particular action causes some corresponding activity on the SCP lines. However, I have theory that the table in the back of the electrical guide is actually the key to decoding and that if you can freeze the data word the header will contain a number in some form, probably BCD but maybe hex, between 1 and 434 allowing you to look up what that message is and it maybe that WDS can take the all hard work out if doing this. I don’t know if the legacy version I have is that clever but I will investigate when I have time as I really like digging into these things.
This problem started when you freed off the trap door in the ignition barrel with some graphite lubricant and it does seem more likely than not that is still the source of the issue. And the tests you did with the fuses indicate that there is an electrical path through the switch with the key removed when there shouldn’t be one. It might be good to start there and review what you have so far.


(Rob Reilly) #31

Thank you for your continued interest in this peculiar problem, Eric.
Touching the battery neg is also clicking the relays with the switch disconnected.


Could there be a path through this connector?

WDS = Wireless Distribution System or Windows Deployment Services?
VMM = Vehicle Message Matrix?
As you can guess, I am a novice at that sort of thing.


(Eric Capron) #32

I think connecting the battery will cause relays 1 to 4 to operate under most circumstances because as soon as you connect the battery the RECM & GECM get a B+ supply and so do the relays. It’s likely that as the modules boot up they will generate grounds for the relays.

Sorry about the abbreviations. WDS is the Jaguar/Landrover Worldwide Diagnostic System and VMM is the Vehicle Measurement Module that works with the WDS.

I bought an ex-Jaguar dealer Panasonic Toughbook laptop with WDS already installed on it. It came with the Vehicle Communication Module (VCM) that connects the laptop to the vehicle’s diagnostic socket. With it you can interrogate the car’s systems, programme keys, fobs and modules and get step by step instructions on fault finding. The VMM has many functions and came with a great many leads and connectors. It turns the laptop into a digital multimeter, digital oscilloscope, vibration meter and various other functions.

Going back to the original problem, we established that when the radio is on with the key out it went off when you pulled Fuse 27 which is on the downstream side of the ignition switch.

Now, the fuse feeding the upstream side of the switch depends on the exact age of your vehicle. The 1999 and 2000 MY electrical guide shows Fuse 22 as the supply to pin 1 of the ignition switch but by 2001 this had changed to Fuse 31 which was the one you pulled previously and which also shut off the radio. If you car is earlier than 2001, Fuse 31 supplies Switched Power Relay 2 which in turn supplies a whole load of other stuff that might have caused the radio go off and so this could be a misleading result. So, I guess to be certain, the next thing to do would be to put Fuse 27 back and pull Fuse 22 and see if the radio goes off. If is does, we can be pretty certain that somehow, the path to the radio is through the switch.
These little changes in the wiring are really tricky and makes tracking problems like this down all the more difficult.


(Rob Reilly) #33

Ok thanks again. The car is a 2000 V6.
Pulling fuse 22 did not stop the radio but pulling fuse 25 did.
This is with the ignition switch connector still disconnected.


(Eric Capron) #34

Have I got this right? With the connector not plugged onto the switch and just left doing nothing the radio still comes on and you still get the chimes etc.? If so, please can you measure the voltage between ground and the terminal that has the yellow wire and if you see anything approaching 12 volts can you pull fuses 27, 12 & 13 in that order and see if it disappears at all. That wire should only receive 12 volts when the ignition is in I or II


(Rob Reilly) #35

Ok, with the connector off, no volts at the yellow wire on the connector. I have 12V at the R/G wire and at the R/B wire.
Pulling fuse 27 and 12 in the rear dist box did not stop the radio. Fuse slot 13 is empty.
Pulling fuse 18 in the primary dist box did stop the radio, but that seems to be in line with fuse 25 in the rear dist box which as I discovered before also stopped the radio.
BTW I have the standard radio and do not have Navigation or adaptive damping.

Edit: re-read your note, maybe you meant fuse 27 in primary box?
pulled fuse 27 in the Primary Dist Box, with IGN switch connector off, which did stop the radio.
Fuse 27 still out, connected IGN switch but key is out, radio started
Put fuse 27 in, radio continued on
pulled fuse 27 and radio stopped.
With the IGN connector connected, but key out, I have 12V at the yellow wire.

I can manually shut off the radio but the clock stays on. It was going off a few seconds after the radio yesterday.
Engine starts fine, but I am afraid to drive it because I don’t know why the battery ran down last week, what’s still on with the key out.


(Rob Reilly) #36

Well, here’s what’s inside my old IGN switch.
pict0044
There should not be voltage on the yellow wire with the key off.
I brought the switch in the house because its really cold out there, and disconnected the new switch from the lock cylinder, and now when I operate the switch with pliers, I have no connectivity between terminals 1 (B+1) and 4 (ACC1) at position-0, so there should be no volts at the yellow wire.
I have conductivity at positions 1 and 2 but not 3 (start) so that seems right.
Somehow the lock cylinder is not turning the switch all the way back to position-0.


(Rob Reilly) #37

I have determined that the tip of my lock cylinder shaft is worn off on one side at the yellow arrow.


It fits into the socket in the switch, but is a very loose fit.
Thus when the shaft is turned back to the 0 position, the switch does not turn all the way back to the 0 position.
Hard to figure how a metal part would wear like that when in contact with plastic parts, but there it is.
I will try to build it up with 2 part epoxy and file it into shape.


(Eric Capron) #38

I’m glad that you’ve found something wrong with the way the assembled switch is working because I’ve been going back through the thread and at one point you pulled Fuse 27 and the radio went off. That’s the fuse that supplies the B+ to the radio and it comes from switch pin 4 (yellow wire). When the plug was disconnected from the switch there were no volts on that pin but it does seem that when the whole thing is assembled there must be a voltage there otherwise pulling Fuse 27 would have had no effect.


(Rob Reilly) #39

Success! Here it is, built up with JB Weld steel gray epoxy, the really strong stuff, and then filed down to the shape that fits the end of the switch.


I also had to file out the inside of the white plastic cam because it had a burr in there and didn’t slide easily on the new epoxy.
Anyway I put the thing back together and checked all the continuities at key in and positions 0 1 2 & 3, all are correct.
Put it in the car and I guess the radio has to initialize or something. It was on before I inserted the key and started the engine, then when I shut off the engine and removed the key the radio stayed off as normal. It works in positions 1 and 2 but goes off at 3 (starting) which I think is correct. Clock goes off a few seconds after the key is shut off. The key-in chime seems to work correctly now too. Doors and boot lock and unlock, no alarm.
No volts at the yellow wire in position 0 but 12V at positions 1 and 2.
Turning the key seems tighter than before, it really clicks in each position, where it was loose and vague before.
And the little trap door seems to close every time.
So I think that did it.
What a roundabout journey just to find it was a mechanical problem after all, a worn out shaft on the tumbler barrel.
And maybe the switch was a bit worn too.
I guess maybe that’s what you have to expect after 230,000 miles.
Thanks Eric and Rodney for all your excellent advice! :hugs::+1:


(Eric Capron) #40

Brilliant result. Well done Rob. Good for another 200k miles now!