Hello all, 97 150, when I try to turn over, clicks at relay under hood but nothing else. All other functions (without starting) seem to be working.
I had to pull the dash to change heater core (fun)!
Everything is plugged back in, truck ran before this process!?

 

Welcome to FTE.

Charge your battery and see what happens. You probably had the doors open, maybe the key on ACC for a looong time. Everything will "work" with a weak battery, but when you hit it with the starter load, the voltage is too low and you get the clicks instead of spinning the starter.

Or jump start it.

If your battery is fully charged and will handle a load (you can get it tested) then work your cables down to the starter and check for corrosion and good connections. A weak battery and corrosion are a sure non-fire combination.

Good luck, report back for more snappy suggestions if this does not work.

 

Turns out I knocked the clutch relay loose when I pulled the dash. Didn't know there was one on the clutch depression rod (keeps you from starting vehicle w/o the clutch depressed). Funny thing is, I've always started it without the peddle depressed, usually disengage the tranny prior to even tuning the key. Now, I have to have it depressed to start?

 

a past owner probably bypassed the clutch interrupter switch, and when you took it apart you probably knocked the bypass loose. then hooked it back up the way it is supposed to be, so the truck will not start unless the clutch is fully depressed.