Time Master Failure
I have had a number of Time Master timers over the years, and I have to agree with Randy that a better replacement is the Dixmore. However before you trash your Time Master it might be worth a little effort to resurrect it.
Remove it from the container box and scrub the circuit boards, with a strong bristled tooth brush, and then spray the entire board with contact cleaner. You might want to look at the boards for, "tracking", between solder joints before you scrub. Also look for corroded, or cold soldered joints. I've been able to resurrect a number of them in this fashion.
The Time Masters have actually served me well, but they seem to be too fragile in the tough service car wash enviornment.
Both the Dixmore and Time Master are from the Denver area. I believe that Morris from Dixmore developed the LED 5 specifically as a replacement for the Time Master, and in so doing he eliminated the weak points, brighter display, less fragile, more flexibility in
coin acceptance and messaging, etc.
Good luck!