Started engine at work and drove home. Went inside and came out after short while and engine wouldn't start. Heard a clicking, like the starter switch was bad so replace it still having same problem. Question is there any sensors that give permission to start truck? This is a 2000, F150 V-8 Triton.

 

take battery in for load test...mine dyed at 21/2 years...got the sears one for trucks...no problems

 

Check the main power cable leading from the starter solenoid to the starter. Mine broke at the starter motor terminal. Ford had a solder on terminal that repaired the problem for about $3.00 (Canadian, or about .50 US)

 

you say starter sw. not sure what you mean. are head lights dim when you try to start. like all most out. then you have battery concern. or are they bright. if bright. there is a starter relay on firewall. by battery. see if that is whats clicking. the trucks have a pats sys. but it will not cause a clicking condition. try lightly tapping on starter when someone cranks it. if starts doing that. starter time. good luck