2001KR4xx4

Hello all,

So, today, I went to go drive my truck as normal, started up fine, drove to my destination and parked. As soon as I arrived to my destination, I realized I was at the wrong place and went to start my truck to go to the correct destination, went to start it and nothing happened except a small, yet audible *pop* coming from under the hood. It was not a clicking noise that would signal a low battery.
Opened the hood and had my buddy try to crank the truck while I looked and listened for anything and discovered said popping noise was coming from the location circled in the picture...


(2001 5.4L V8 134xxx miles) It is a box-looking thing behind the battery, and I personally do not know what it is for, hence why I have come to the forums for guidance!
my questions are...
1. What is this box for?
2. What in this box could be making said noise and not allowing my truck to crank?
3. Could that noise be nothing of importance, and it be my starter/alternator?

I checked the fuses in the cab and referred to the manual to see which ones were starter related, none were tripped.

It was about 40*F outside when this all happened, and I recently had my battery tested to find out it was getting close to time to replace it.
Tried having a friend jump start my truck and same thing happened when we did not try to jump it.

I am just confused as to how my truck would crank perfectly one minute, then not the next. And need to get this fixed as soon as possible.

Any ideas or solutions to this problem would be greatly appreciated!!!

JCR 56

The popping noise is the starter relay on the firewall. I would check all connections for corrosion even at the starter, some cables can corrode under the insulation making it hard to detect. If no corrosion or loose cables anywhere, could be a starter problem.

jprevat

iTrader: (1)

Easy way to find out if that is the problem. Turn your ignition to the run position and take a pair of insulated handle pliers or screwdriver and touch both terminals. If it turns over you found your problem. Hold it there with pressure and your truck will start.

twoskinsoneman

Second the connection route. This has happened to me a couple times. Make sure battery connections are tight!

Jbrew

Right, I use a screw driver, but that will test the relay..narrow it down some. It should start right away with this test...In park, key to run position.

2001KR4xx4

Well, I was able to do the screwdriver trick, (but had to use a pair of pliers instead), got the truck to start and made it home. I had to clean the connections on the solenoid cause they were covered in dirt, but after a little spit and shine, it jumped the connection and started right up! It must just be the solenoid so I will be replacing it soon this week!
Thank you all for your impute and advice!!
This website has saved my butt more times that I can count!!

Jbrew

Guess I should of mention the screwdriver I us is a very large and ugly Craftsman. It doubles as a big pry-bar as well lol. Never tried it w/pliers.

Well glad it worked. The relay is good, don't replace it. Check that in line mini fuse in the alt harness. It should be encased. Check the fuse and make sure it's plugged in good. Those plugs can widen and they can short without you knowing it.

Clean up all your connections.

jprevat

iTrader: (1)

Good luck. Glad we could help out. For as cheap as the the solenoid is I would more than likely replace it as well as check the fused connection Jbrew was referring to.

Jbrew

The Motorcraft isn't cheap lol.

jprevat

iTrader: (1)

This is true but I tend to have spares laying around. I have a spare starter selenoid, serpentine belt, coil, plug,quart of oil, and e-fan contoller in my truck all the time.