Replaced battery; now won't start
 

I had a dead battery in my 06 F150 Super Crew today but when I replaced it, the truck won't start. All the other electrical components (radio, lights, etc.) seem to work fine, but nothing happens when I turn the key. There is a clicking noise coming from under the dash on the passenger's side -- is there a relay or something that could be the problem? Thanks

The clicking noise is your starter relay. It should be delivering power to the starter solenoid, which in turn, gets power to the starter motor. You need to see if the 12V supply to the starter motor is good, and if it is, try to find out why the relay is not causing the solenoid to act.

Since the relay activates, I'd say your ignition switch is fine.

- Jack

The starter works -- so is the relay faulty?

Ahh - did you jump the terminals to the solenoid? Is the starter actually turning the engine? (I'm just trying to make sure you didn't simply apply 12 V to the motor itself, bypassing the solenoid.

Assuming the solenoid is ok, the relay COULD be bad, but these devices are pretty reliable. I'd be more inclined to suspect the electrical circuit between the relay and the solenoid. I haven't looked at this closely, but could you connect a jumper wire (alligator clips on both ends) from the relay "out" terminal to the solinoid "in" terminal (I think it's the "S" terminal), but you should be able to trace the existing wire to see which terminals to use.

Before you do this though, check fuse #101. It's a 30 A fuse that sends power through the starter relay into the solenoid coil. The relay itself gets power through fuse #102, which is probably good, since you hear the relay clicking. The relay itself is on the Central Junction Boc (fuse box) and may not be replaceable as a separate unit.

Edit: I should have mentioned fuse #101 at first, but I wasn't looking at an electrical diagram then.

- Jack

Hey man,

Sounds stupid, but I had to clean the battery corrosion powder (light green crap on the posts) off this morning because I had the same sound coming from passenger side. Irritating as crap. I have yet to find anything to help. I'd assume you already cleaned the clamps before putting in the new battery but it takes a suprisingly small amount of powder to get in the way and prevent enough contact to give you the flow necessary to turn her over.
Might help.

-Dave