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wild weird rear windows issue in a 99 convertible xk8
hi all,
so i loaned my 99 xk8 to my friend and she was driving it home from work on the highway, and as she is driving, for no obvious reason, both rear windows go down. she was not touching the roof button and she was going fast at the time. the check engine light has been on for a while now, but the car drives normally otherwise.
when she stopped, i got her to turn the car off and on, and use the roof button, and the roof worked, but the rear windows remain down.
this is an extremely frustrating situation. any help or tips? i think the window motors are fine, i think its just a faulty sensor or something like that, maybe due to the extreme cold here in NYC.
Mike, first thought test(eliminate roof switch). Insert key in driver door turn key clockwise and hold (north America) to open all windows, then roof. Counter-clockwise to raise roof then all windows. Rear window works? Switch problem.
Second thought: low battery.
Do you have access to a battery charger? If so, hook her up.
Doesn't fix? Do hard reset. First put your keys in your pocket. Disconnect negative cable at the
battery. Touch negative wire to positive, hold for 10 - 20 seconds. Reconnect negative wire to battery.
Reset front window travel (remember how?). Start car try windows.
Rear right & left windows are on separate 20amp fuses (trunk fuse box slot #12 & 20) so I didn't start there, but hell stranger things have happened.
Thx John, great post, I had to take it to the dealership in Manhattan here bc of the weather but I will def reference them to this post!! Thx again, -Mike
Yeah from what you said, it’s probably a sticky sensor due to the cold but.... you did say “.... she said...” so (trying not to sound sexist) are you sure of the facts.
+1 to John above but just to add that resetting the system should be from completely open (top down, rear windows down) or completely closed.
If you need to urgently close the rear windows and pushing button doesn’t work, you can jump the window relays in the rear trunk fuse box.
as to your concern, i mean i have no reason to think the facts aren't as she described them. i showed her the roof button before she drove the car, and she has had it for a couple weeks. the weather here is terrible, and she was driving home from her work on a freeway. so i don't see a scenario where she would want the top down. plus, at that speed, i don't think the roof button works, right?
so assuming she was going fast down a freeway, and assuming thats when the rear windows went down, what could she possibly have done to make that happen? and even if she had stopped and operated the roof button, why now won't the rear windows go up? (the roof itself works) no, i completely believe her that the rear windows suddenly went down without warning and without rhyme or reason while she was going fast down the highway. i love this car, but it is a pain in the ***, lots of quirks to put it mildly.
what i don't understand is if speed disables the roof button, how then did the rear windows sensors get the idea that at that moment, they were supposed to be down? like its just truly odd. i've been searching the forums trying to find users with my era car who had similar issues, but its hard for me bc i'm not much of a mechanic. i did find this thread, but if anyone finds any others, i'd be very appreciative!
How old is your battery? Failing batteries can cause some very strange issues in these cars. When the original factory battery in my wife's 2006 XK8 began to fail back in September 2012, the car would randomly pop the trunk open even if no one was in it or near it. This happened multiple times over a week-long period before I finally figured out that a dying battery was probably causing it. A new battery indeed fixed that problem....
i have had the battery replaced a few times actually, and it can get weak. this is mainly bc the car can go thru long periods of not being driven, and exposure to long bouts of cold. but whats weird is the car has been starting in the cold here pretty reliably. i have considered that the battery and or alternator might both need replaced, but again, that this happened while going fast down the highway, it just seems odd that power at that moment would be the culprit, altho i by no means rule it out.
Failing batteries can continue to start a vehicle and allow the vehicle to operate normally for a period of time before they finally die. Keep in mind the old adage that any battery can fail at any time....
Driving these cars on a regular basis goes a long way towards keeping them operating properly. My wife's 2006 XK8 has not been her daily driver since late October 2018. In fact, she has only driven it once during the past 18 months. So I make certain that I take it out twice a week for at least 20 miles of vigorous exercise. It stays much happier and healthier as a result....
+1 to Jon89, as a failing battery is the no1 suspect for electrical gremlins in our XK8. Plus it's the easiest thing to fix and should be the first thing crossed off the list of potential suspects. You say that you're not a mechanic, so be sure the local garage mechanic is aware of the system control of a hydraulic control top, which BTW is common in our era of car. Dodgey connections, which just need to be cleaned/tightened, are common faults due to the age of our cars.
There are other suspects, such as a sticky sensor, esp. considering the cold weather you're experiencing. One of the hood's hydraulic drive ram (rear right - when looking forward) has a sensor built into the bottom of the ram, which is known to fail. I did change this ram in my car, due to a leak. Some pics below.
Behind the rear right interior panel (looking forward) with speaker taken out.
Bottom of the ram with the sensor connection at the side.
Quick question - Was the car parked outside exposed to the elements?
so on monday, the jag dealer wanted to charge me $598 for a new battery (just the battery, who knows plus labor, diag, etc). they claimed the battery i have is shot / wouldn't hold a charge.
i have an interstate battery, under a year old. i said, no the battery should be fine and is under warranty.
they said they could get the rear windows to go up, but they would just go down again bc of the battery. i said please charge the battery overnight and i will pick up the car tues.
on tues, i got the car, the rear windows were up and staying up. i took it two streets away to cybert tire. they did a test and said the battery itself was fine. they said the alternator was low, at 13.x volts, but the battery is full and idk how much load the car was pulling during the test, (although they said their test is at full load, but idk how if they didn't turn on all my car stuff). but anyway my mechanic in PA said he thinks that reading for the alternator is normal bc the battery was full.
so anyway, my friend is borrowing the car again, and so far so good.
the jag dealer btw ended up not charging me anything at all, which i thought was decent of them. i did point out that to them that a month or so earlier, they told me my transmission was shot and would cost me $13k, even though i told them i thought it was a computer issue, not really a transmission issue. turns out i was right, my mechanic in Pa saw that the ECU unit (is that the right abbv?) had some corrosion from water, etc, and cleaned it and sealed it and so far, no issues. cybert tire charged me $80 or something like that for the battery test, which kind of annoyed me to be honest, but it is Manhattan and the guys there were nice enough. they gave me an estimate of $850 or so to replace the alternator.
i suspect a lot of my problems with the car have to do with the power / and or moisture around jag electronics. so, jag chips, and battery and alternator. why? b/c i added a native DC power based computer to the system. i have it disconnected right now. it is jacked into the native alpine system via an alpine adapter. the computer turns on and off with the car. but idk if the alternator is enough to keep the battery good and run the computer and all the other stuff at the same time?
gremlins.
i couldn't talk to the jag techs at the dealer directly, (its not allowed), so idk if they did a full roof cycle or what, and i never got an answer, beyond 'battery problem' as to why the rear windows went down to begin with.
thanks to everyone for your replies! i will update if there is more to say, please lmk if you have questions or want clarifications. thx again.
Why in the hell are you still going to that dealership? Most Jaguar dealerships are now clueless with these XK8s/XKRs. Some refuse to even work on them....
Find yourself a well-respected indie shop for the jobs you cannot do yourself. Avoid the dealership like the plague....
Mike were you referring to Manhattan Pennsylvania? None of us could imagine a dealer in manhattan NY not charging thousands for just looking :-)
BTW I didn't even realize there is a Manhattan Pa.
Mike take the car to an autozone. They will check alternator for free. That's how I ID'd my faulty alternator. FWIW there's really no complicated mechanical knowledge needed to change your own alternator. If you've got a decent ratchet wrench set and an afternoon you can do it. Lots of bending, reaching, cussing, but low difficulty level.
third, i took it to the dealer a month+ or so ago bc it was nearly undrivable in limp mode giving those error messages due to the moisture, and the dealer was the closest option that might have a clue. my friend took it to the dealer for the rear windows, bc its conveniently right near where she lives on the UWS.
driving anywhere in the city or out of the city is a pita, takes time, is a risk, and costs money. frequently, whatever is closest or most convenient is what ultimately makes the most sense.
i very much appreciate the advice here, but i really try not to do mechanical stuff on my own. i simply don't trust myself to do it.
i did however, just get one of these, and i'm excited to use it with my phone. (Kelchners has the same one, so we can diagnose things remotely)
wild weird rear windows issue in a 99 convertible xk8
