2000 F150 4.3L v6, straight drive, no power W/L. Pulled in my drive way, cut the truck off, realized I needed to move tried to immediately crank back up and nothing happened. As soon as I truned off the ignition I tried to restart. I check the fuses and relays. The #2 relay under the dash is clicking while the main batter wire is connected to the battery. Head lights do not work, however clicking on #2 relay stops when headlight switch is turned on. There is 12v everywhere there needs to be - at the starter, in the fuse panels, no fuses are busted. There is a theft light that lights up on the dash when I try to crank it up. Could the truck be locked up by the theft protection? Nothing happens when the ignition is turned on with the proper key. Thanks in advanced for you help!!

 

First thing is, measuring 12 volts in this kind of situation means nothing.
You likely have corroded battery cables or even a battery with an internal cell strap gone open from vibration.
What I mean by the first statement is, when a heavey draw is requested by a starting action, a very poor cable connection cannot support the heavy starter current draw because the bad connection (drops) all the voltage accross it and leaves nothing for the starter or the rest of the truck to operate with.
So a voltage measurement does not mean a whole lot.
Check all the cables out, clean and be sure they are tight first as an elimination, then proceed to have the battery checked out.
The click is the starter relay pulling in but the power is not there to go to the starter.
Good luck.

 

I actually just had a new gold top battery installed a few weeks ago. All the connections are solid, with no corrosion. The number 2 realy under the dash is titled as the ECM (Electronic control relay) relay. I even swapped out relays (b/c they had the same part number) and the other good relay still would click (or engage) - but when I would turn the light switch on, it would stop. Could this be a problem with the computer of the truck. Nothing is happening in the truck...no lights, nothing. its dead...