I kept having problems with mine and found the battery contacts were
corroded. I sanded them with a fingernail card and used petroleum jelly
when
installing the battery.

Hope this is your problem.

Frank

thanks Frank, i went out just now ( night time ) and checked it, it looked
just fine but i cleaned them anyway, but it still didn't work... i did
notice though, that the keys lit up like it was getting juice, but when i
entered the code, all the keys would flash for about 5 seconds and then
quit. anyone know why they would all blink like that ?