On my 2008 tahoe that has the touch screen radio,the clock has dissappeared. how do i fix it.i did disconnect the battery last week end.

Check grounds. Battery to engine, battery to body and engine to body. Battery to body will corrode. engine to body is usually the first to break.

i cant understand your post. "have time" and (it wont come on) and
or you can use touch, << did you mean Can't ?)
tell that which works and does not. (
media center 730n? this failing
with Navigation?

get it serviced,?
this is what we call the magic features, Uconnect.
(window dressing bad?)
DIY ? what are you asking?
Help to do WHAT.?

or check fuses.
is car battery charged to 12.6vdc rested???? or at below 11v.?
does car run and drive? perfectly,

in the shop, they checks fuse, and battery voltage.
then they scan the PCM for errors, if they have errors the fix
that first. like bad comms to u connect/nav, radio , ,etc.
then work up to the actual head. finally replacing it.

these are fancy , complex to the max , high end options.
and when they bust are expensive to fix. '

my guess is you have this system.?
AM/FM (1-CD/DVD/MP3), full map navigation (6.5" integrated touch screen display), 1-disc data drive,
integral satellite & input jacks (RER)

"These radio receivers can only be serviced by an authorized radio repair station. See the latest Warranty Policies
for a current listing of authorized radio repair stations"
this means very special tools are needed to fix the unit
and access to special software updates in the unit.
go to the dealer an get just that.

First before I post...Do you have a amp meter?

If you disconnected the battery then the anti-theft system engaged. The radio says locked may be refering to the computer as well. The system must be reset. Check the owners manual if you have it. Otherwise, you may end up having a dealer reset it. Thousands of people do this everyday.

You do not use OHM's to test any battery or ground cables/wires

OHM's is seldom used anymore & always on a circuit
disconnected at both ends or a part by it's self

OHM's uses the 9v battery inside the meter to load the
circuit being tested.

You switch to VDC & go from the battery neg to any metal
or fluid on veh,to test for a voltage drop

Should be no more than .02 V (2 tenths of 1 volt)
Same on Positive Side Cable to starter

If you go from the Pos Post across to ANY metal your
on the ground side & see a voltage drop equal to the battery
charge at the time.

You always have at least 40 mili-amp current with the radio clock,
relays,ecm/pcm,modules,etc,they do not sleep

by disconnecting the battery you have activated the anti-theft system in the radio
you will now need a code and insert it in the radio before it will operate again

Fix your car right away by clicking the link I attached
2008 Ford Escape Workshop Repair Service Manual PDF Download

all vehicles use a certain amount of power nowadays, its the keep alive memories of the computors , radio for channels and clock etc, although this drain is minimum it will drain the battery over a period of time, just like a cell phone even if you are not using it it stays alive , either get a trickle charger of disconnect the batt , hope this helps

If the battery is the factory OEM since you had the truck. It may just be at the end of it's life, most battery last only 4 to 5 years and then needs to be replaced. You can always disconnect the battery when you park it over night and see if the battery has keep it's charge. Just make sure you turned the radio off first before you disconnect the battery. Start with this and as for the 4wd switch, that would not pull any current when ignition is turned off. Good luck and keep me posted.

some time the battery CCA are very low , not having enoght amps to crank the engine, but enoght to turn on the radio, and clock, also check the battery terminals , dirty termanls can cause what you explane