The touch screen doesn't work with my finger tip, only when my nail touchs screen, also did the screen calibration, did not not help

SOURCE: Garmin 2610

Back up the unit then do a master reset.
Switch OFF, Press Page + Menu and turn on, holding the buttons for 5 seconds.
Then recalibrate. I did the recalibrate a few times before it was OK. If you use a stylus when the cross appears and hold it on the screen and move it to the corners you can see the error. Make a mental note and go halfway between the two if it does not calibrate at first go. Then when it calibrates, do it again. I recalibrate every now and again. I think it could be a firmware problem. I will try going from 4.8 to an old version

SOURCE: Screen Calibration problem with SteetPilot c330

Turn off the unit. Then hold down the power button for about 1 minute and the calibration screen will eventually come up.

SOURCE: touch screen won't calibrate on garmin 2720 gps

The touch screen is a 4 wire resistive type made up of several layers. A thin plastic layer, a micro thin metal layer, microdots for insulators, another ultra thin metal layer, and a final plastic layer. All of these layers amount to the thickness of a sheet of paper. This whole stack is bonded to a thin sheet of glass and placed over the actual TFT display.

It's amazing that you can see through all these layers and only lose 20% of the light. What's not so amazing is that those thin metal layers are prone to damage. I've seen several with no apparent damage that didn't work, and several with visible scratches or cuts that worked fine.

I usually start by installing (or reinstalling) v7.2 firmware and then attempt to recalibrate the screen, sometimes that works. Next I would try re-seating the 4 conductor touch screen pigtail in it's ZIF socket nestled between the big white wires on the display assembly. The last resort is to buy a broken 2600 or 2700 series Garmin and salvage the touch screen. You could send it to Garmin for a flat $250, but that makes no sense at all.

If you get another screen (Garmin won't sell you one), Here's how to replace it:
Remove the six screw holding the case together.
Split the cases and pull the patch antenna out of it's slot.
Remove the four silver screws holding the display assembly into the front bezel.
Unhook the small ribbon cable that goes to the infrared receiver under the red lens.
Pull the display assembly out of the front bezel. It won't come all the way out because of cables.
Use a razor to cut the plastic tape holding the touch screen bracket to the TFT display.
Unlatch the 4 conductor ribbon from the ZIF connector nestled between the 2 big white wires.
Use a penknife to unbend the metal tabs keeping the touch screen from coming loose. I usually just do the two by the IR receiver.

When you reassemble, don't get frustrated with the gaskets, they're tricky but it can be done. Tom

SOURCE: my garmin 255w's touch screen is messed up

There are three ways to fix it

Recalibrate

remove face cover and use the reset button or the sequence from the manual to reset factory settings

Finally.... send to Garmin

SOURCE: garmin nuvi 1350:touch screen calibration

Hold your finger on the top left corner of the screen while turning it on. Release the power button when you see the Garmin logo pop up but keep your finger on the top left corner until the white calibration screen shows.