New Battery Fixed Two Issues
 

About two weeks ago I started getting two errors on the dash; one said "Cruise Control Not Available" and the other said something like "check taillights" (I forget the exact wording). They would always come on at the same time and then the display would alternate between the two. I was thinking that I had a problem with the brake pedal microswitch and I was going to replace it this weekend, but then a few of days ago the battery went dead. I thought maybe I had left the lights on, or that maybe the brake pedal microswitch was stuck in the "ON" position and it caused the battery to go dead. I jump started it, drove it for a while and charged up the battery, but the very next day the batt was so dead that it wouldn't even click when I tried to crank it. The last time I got out of the car I checked to make sure the brake lights weren't on, so I figured I just had a bad battery.

Yesterday I got a new battery, and since then I haven't had an issue with the two errors that I had been having. When driving last night I also noticed that my HID headlights were flickering like they had been doing sometimes in the past. And now I'm wondering if my battery was just weak towards the end of my road trip when I had that transmission problem. That makes sense because my headlights were flickering like crazy at the time, and the transmission fault actually occurred when I flicked on my high beams.

So, I've read on here that a weak battery can cause all kinds of weird problems, I'm thinking that may be what was happening.

UPDATE! This didn't fix the problem after all. Jump to the bottom of the thread.

yup, could very well be related! Haven't seen you online in awhile...bizee?

BTW, how's the car sale going? Dan (MrTexasDan) hasn't finished his fuel filter document yet, sorry about that. I contributed but its his document.

I advertised it on Craigslist but I didn't get any hits. I haven't been trying that hard. This weekend I plan to advertise it on cars.com.

low battery?
 

Hi, a good experience. What was the battery indicator showing with the engine at idle and during cruise?
Mine is showing 13V all the time - I wonder if the battery is not weak as well...

OK, I was wrong. I definitely had a battery issues, but the "cruise not available / check rear lights" issue came back. I had a problem with the brake pedal microswitches. I fixed the switches, but I swear, that was the biggest pain in the ass in the history of pains in the asses. Read this thread for more info.

Regarding the flickering headlights, check the connection in the trunk where the ground wire from the battery is connected to the car frame. A poor connection here can cause the flickering.

Food for thought captom. According to my jag service writer the gauges will always register normal unless there is something way out of wack. I ask them why they do not move as engine performance changes. I was told that Jaguar errored on the side of normal than to have things read as they really were to keep the complaints down. People bringing their cars because the gauges were reading different from idle to crusing speed. That is what I was told any way. But we both know the oil pressure will change when your going 60 vs going 25. Watch your gauge next time and see if the oil pressure does not move at all no matter what speed you are driving.

Thanks daddyo007. Seems would be better for the people not to have the dials at all - nothing to watch, no worry, no complaints to service :). Ok, I just wanted to know what is normal battery voltage reading during cruise before I take out the good battery and start charging...

When my battery starts acting up the first sign is that the windows will not hold their set position. Just a slight drop will cause this problem but every thing else will be working fine.

My cruise control has quit working, the button on the trunk itself doesn't open the trunk while the in-car trunk open does, windows sometimes loose their fully up set position...this is the original battery on this 2002 XK8 so I'm wondering if the battery could somehow be causing the problems? Yeah, it's probably time for a new battery before it goes out even though I'm not having any other problems, but these particular issues seem odd to attribute to an old battery. Am I wrong about this?

PS: I'm not getting any messages displayed.

The window thing is a classic weak battery indicator.

The button on the trunk lid is probably a broken wire ... the repeated up and down of the trunk lid stresses the wires. Happened to my '01

Cruise control, I dunno.

I was having cruise control issues when I had a weak battery, but I also had a bad brake pedal switch, which also affects the cruise control. Like Dennis said, though, the windows losing their memory is a classic sign. Take it to Advance Auto and they'll put a load tester on it and let you know for sure.