Hi. My Jag head lights have started this blinking thing. As I am driving they will blink for no apparent reason. There doesn't appear to be anything going on otherwise. Any ideas where to start?

First thing to do is have the computer checked for trouble codes. The blinking D4 light means overdrive is not going to function, probably because of the rough running engine.

the problem you have is caused by the pats anti theft system is not recognising your key it may be the transponder or you may need a new key and get it programmed by a jag dealer or someone with the needed gear to do it with best advise take it to a jag dealer

Hi there, First I need to know when you insert the key and try to start did it crank? Did all the light on the dashboard lit up like check engine, abs oil battery ect... ?? If so is the Secrity light blink? How long do you have the car? Did it ever do it befor ? I need to know more about you car.

First, go around the car and tighten all the locking mechanisms.
A loose one will report 'door ajar'
This would explain 1 and 2.
3 sounds like the ride level sensor under the rear suspension.
Have you run over anything interesting lately?

sounds like there is a problem with the day time running lights my does the same thing but because i installed HID light so i no long have day time lights try changing headlight bulbs if not then its a short

When I'm driving, specially since it's been snowing out recently my TLC light or whatever it's called will start flashing "TCL Off" even though I had it on, is the car doing this for a specific reason? It stops blinking when I hit the off button on it but then it just stays solid and stops blinking. Anyone have an idea as to why it does this? When I bought the car it did not come with a manual so I have not been able to look it up and can't find anything about it on the internet.

problem solved mechanic had wires on wrong thanks

The long story short it probably your battery being dead or a computer glitch (if there is nothing else apparently wrong with the car)
One is the battery life of an older model jaguar is going to be short compared to newer models. I noticed I have problems with my battery going dead around the 6 th year of the cars life since then a bunch of silly issues. One thing to know is if your car doesn't start it (even if your lights work) is that your battery is to low for the ignition to work (which requires high voltage). You can try removing the batter than re attaching it back to the car.
I have these issues typically when i don't drive for long periods of time in the winter (mostly). The car contains a big gigantic computer (which a lot of owners do nt realize) controlling everything weather you can start the car or not (it has a security system still armed) so when the computer is not working properly or the battery is too low (and their are no other apparent reasons). I would suggest trying a few suggestions on the jaguar forum because its very specific but you would be surprised how stupid the issues end up being. Flat bed a jagaur to any dealership and your already in the hole for 150 plus.
good luck

sears.com has the manual for your car for $17.99 on sale

first, i would bring the battery somewhere like autozone, where they can do a free diagnostic check. definately sounds like a battery problem to me. a bad starter should not have that affect on the entire electrical system and will not work if there is not enough current available. if the battery is not the culprit, you may have a bad relay or fusible link somewhere, but i am willing to bet it is the battery.