One wall jack had no dial tone. Installed new jack. Wires were black/yellow/red/green

Hook them up to the jack terminal that have same corresponding colors. But still
No dial tone. Guess it may be in the line??

If you have a Multimeter, measure voltage between the green on one lead, to the red, yellow, black, try all combinations until you find about 48 volts, the lead that is negative will hook to the red on jack, the positive connects to the green.
If a phone is off hook while you are measuring, it will be less than 9 volts