1987 f250 with a swapped 1989 7.3 idi

[fordmike]

hi i got this truck about 3 months ago and she was running fine until the colder weather set in and last week i went to start it and it just clicked well me being a diy mechanic i found it was the starter mounted solenoid i replaced with a a new one from auto zone well it started fine for a week and when i went to go to work this morning it did it again now i am wondering if i have a short some where in the system but i dont know where to start please help i just dont want to keep replacing the solenoid