As a followup to the recent thread, and thanks to all for the useful information! The Honeywell part number ZD30S60C02-Z seems unavailable at Digikey (note: not 'Digiking' as offered in the thread), Newark, Mouser, or any of the online sites I have used. I did find it on Amazon (2 pack) and at Primelec.com, from whence I ordered two pieces. If this is any indication, the switch may be becoming hard to find.
I had concluded - after much head-scratching - that the only thing in common between a 'check rear lights' (which are all working perfectly) and 'Cruise control not available' is the brake switch that is involved in both; one to turn on the stop lights, and one to disengage the cruise control. It appears from the thread that only one switch is used for both tasks.
Has anyone published the procedure for replacing the switch (I must say that 'getting on a bit' and having a bad back, I don't relish laying on my back in the foot-well, with the brake pedal against my nose, a flashlight between my teeth, and my legs either side of the seat back :[ , so I would appreciate any words of wisdom. Also, how come my code reader doesn't see any fault codes? After 'clearing' the two errors whilst driving, the yellow caution goes away when I turn off the ignition, and doesn't come back on straight away until, presumably, I touch the brakes or hit a bump. Before that, I can get cruise control.
Last question: it seems as though there is no power switch for the cruise control, at least in my 2005 XK8?
Thanks!

 

There are two microswitches, one normally open, the other closed. When you depress the pedal, the normally open switch closes to provide power to the lights, while the normally closed switch opens to disconnect the cc.

A generic code reader does not read body codes, which are Jaguar specific.

The power switch is to the left of the sport switch just below the shift lever gate.

 

Many thanks for the reply. Having ordered two switches, which I assume will perform either duty (NO or NC, as installed and / or wired) no doubt both should be changed.
I am puzzled as to why a Check Rear Lights message occurs (bogus) at the same time, every time, that the cruise becomes Unavailable (genuine). What drives these switches, the pedal directly , and are they mounted to the same bracket, and where should I look for them? Are they adjustable for 'sensitivity'? Thanks for your help.

 

My read is that when the control module detects an inconsistency with the switches (NO and NC, on the same lever, off of the brake pedal stem), it informs you that the brake lights are not going to be operated anymore as well as the cruise control becoming unavailable. Remember, most things in the car are wired in to a control module (computer) that has coded logic to make decisions based on input. There not that much of the old style direct wiring anymore.

There is definitely an adjustment built into the switch trigger. There is a ratchet/slide that makes the trigger engaged earlier or later into the pedal travel.

 

Many thanks! I was also interested to read the clever idea published last year by MDIAMOND. The technique is to drill a hole through the bracket that holds the switches, from under the hood. He then fed a wire through the hole and into the footwell, where he kinked it (to prevent the assembly falling off. The two bracket nuts were then removed and the switch assembly dropped into the footwell, still attached to the wire. The switches are then replaced and the assembly pulled up into position using the wire. This sounds like a two person operation; in my case, husband and wife! His goal (and mine) is to minimize the discomfort involved in brake switch replacement, and I shall give it a try. If anything additionally useful is learned, I shall report back. Thanks again for all of your input.

 

It's not necessary to remove the bracket. The switch is held by two nuts. Remove the bottom one back off the top one,hen back off the nuts in the engine compartment. You can then remove the switch by bending the bracket a little to free it from the pedal.

I don't think the micro switches are identical. I recall Jon89 listing two different switches in a previous thread.

 

Great tip, thanks! I looked at the images posted by SGTofMARINES in 2010, which gives a picture of what you are saying. May I assume that the plastic housing containing the switch / switches comes away from the bracket in one piece, and that the housing can be dismantled for switch replacement? It is not possible from those shots to see the bracket and switch assy in the installed position, so I hope those nuts are accessible and visible?

 

The nuts are 10mm, and while the top one is not very visible they are accessible. Yes it comes away in one piece. It's much easier if you remove the seat.

 

RJ237,

I believe the two microswitches on the assembly are indeed identical. I listed two different sources for them, not two different actual microswitches. If I recall correctly, the part numbers were different because the source vendors were different. So hopefully either of these two microswitches will work regardless of where you source them from....

 

Just checked my notes from the last time my EE friend re-soldered two new microswitches onto my spare brake pedal switch assembly (that was in November 2016). The two sources (and two part numbers) were:
- DigiKey.com, part no. 480-3630-ND
- Honeywell Switch, part no. ZD30S60C02-Z

Supposedly, either one of these microswitches will work. If I remember correctly, one of them is more difficult to find than the other. That may be because one of them has been discontinued by the manufacturer....

 

Thanks all! The Digikey p/n didn't work when I used it at heir site. The Honeywell one did (as it did for Mouser and others) but the stock level is zero and the required re-order qty was 1,000 pieces at one site. Digikey simply said that backorders were not allowed, so it wasn't even possible to place an order at all.
The place I cited - Primelec.com - does have them for sale and in small quantities. Without some digging I don't know if that switch is the same as used in the window-drop sensor, but the latter seems another certain item for all of us, eventually.

 

Hi Everyone,
I am new to this thread and I experienced the exact issues.

Only that I did managed to install a brand new OEM Brake Like Switch, and very sadly, it doesn't fix the problem.

I was able to verify the brake light switch is indeed NOT defective, that is the 2 outer pins are normally in closed circuit (resistance is near zero); the 2 inner pins are normally in open circuit (no resistance)

Now I am really struggling what is going wrong here. I have checked all the rear light bulbs and connections. They all seem OK.
I also noticed that the dual msg usually will show up soon after I applied the brake a few times regardless of how far or how fast you travel.
If I stop and re-start the engine, the dual msg will clear until the next cycle.
It is intermittent but very predictable.

Does anyone has similar experience and how you go about to fix it? Thanks for sharing

 

I have yet to attempt a fix (can't decide whether or not to pull the seat out for easier access, even at the risk of permanent back injury), but as I understand it, there are actually two switches, and either one causes the same error message. Hence, in my case, the brake lights are perfect, but the cruise won't work (once the error has occurred, and I concur exactly with your sequence of events). As there are three things standing between us and happy motoring: functional switches (2) that are wired to the correct NO/NC/Common terminals, functional connections to said switches, and correct adjustment of same so that they close / open as designed, if the switches you installed haven't cured the problem, unless the wiring is broken somewhere (at a connection, for instance) the answer seems to lie in the above three possibilities. Somewhere.

 

Hi Atlastajag1,

It sure is an interesting "Jaguar branded" electrical issue to say the least. I guess this is part of fun factor of owning a Jag in this era..LOL. Mine is a 2006 XK8 Victory Ed with just 30K miles, and I have just encountered this issue last week, so it is still fresh in my mind...

Also it is interesting to note that to recover from that condition, just turn off/turn on the engine. The dual msg will go away and you can use the cruise control until the msg is displayed again.

This to me implies an electrical contact problem. I am going to re-solder all the wire leads in the supposedly brand new brake light switch and try again..will update soon

 

Thanks to all for the brake switch diagnostics needed to identify/solve the "check rear lights - cruise control unavailable" message problem. In my experience, the switch is very sensitive to its positioning/fit to the brake pedal actuator arm. Looking at my switch, I noticed that the arm engaged the nylon switch piece at the top of its travel. It engaged with a lot of play and made questionable the full open/close contact of both the micro switches. The closing distance of the switch piece is adjustable, as described, and may cure the problem. My problem was the actuator arm was not striking the switch piece perpendicularly. I was able to correctly position the switch by lightly bending it outward to the left, so that the strike was perpendicular. The movement of the switch also shortened the travel distance to where the switch was fully activated, so I did not have to do a position adjustment with the built in slide ladder (at least not for now). Don't know how long this tweak will last, but for now, a simple fix and one less annoying fault message.