Electrical Issue?

cubewhiz · Oct 6, 2011

I got to work with no problems, but when I went to go home, the truck wouldn't start. I popped the hood and pulled the terminals, cleaned them up, and tried to start it. The lights would go on, but as soon as I tried to start it, all power was gone. No lights, nothing. All the wires seem to be tight.

I was able to get a jump start. It started up, but after I got about 50 feet, the truck shut off completely. All of a sudden, no lights, no power at all, and it wouldn't start back up.

After I got towed back home, I fiddled around with the terminals again and it started up. The terminals were tight before and there's no corrosion on them, so I'm not sure why it would start now, but not before.

I'm thinking it's an electrical short, but I don't really know. What could cause this? If it is a short, how can I find it? I looked under the truck at night when I finally got it running again looking for blue arcs, but I found nothing. I'm afraid to drive it now because I don't want it to just cut out on me again.

Any advice is appreciated. Thanks!

killj0y · Oct 6, 2011

Sounds like the alternator is dead

Sunk · Oct 6, 2011

Could be the alternator, or if you heard a clicking sound while to start it check out the relay on the inner fender.

Brandon Nootenboom · Oct 6, 2011

It could also be the voltage regulator which on my 97 4.0 is removable on the back of the alternator, you can take your alternator to just about any parts store and have it tested usually for free, that will tell you if the alternator is ok. Also if you know how to use a voltage meter you can test the charge (or lack there of) to the battery. You also should also put a charger on your battery and may want to have it load tested as well, most parts stores can do that free too

tammyleigh69 · Oct 7, 2011

i had same problem.i cut off the factory battery clamps replaced with new.
the thinner wire going to the + clamp was bad.it looked real good but was bad.
how i found it was wiggleing wires

lil_Blue_Ford · Oct 7, 2011

I'd suspect a bad ground somewhere if you were able to fiddle with the wires and get it started without a jump. It is possible for the ground wires to look good but be corroded from end to end, I went through that mess with my choptop. Battery was good, alternator was good, but it would cut out on me for no apparent reason. Couldn't figure it out at first till I was playing with the ground wires and heard a crunchy sound. Cut some insulation off and found it was corroded in the casing. Couple new wires and a liberal application of dielectric grease to the ends and it was good.

But it still wouldn't hurt to have the alternator and battery tested.

cubewhiz · Oct 7, 2011

I don't think it is the alternator or battery because the battery seems fully charged. Before I got it started, the lights shone brightly and while started, the Voltmeter read normal. I can pull them and take them to AZ to get them tested anyway tomorrow.

Bad ground seems like a likely scenario, actually. I just replaced the main battery to body ground about a year ago. I posted the thread on here. I will look into the grounds tomorrow.

Nobody else mentioned a short, so that seems to be a good sign. I hate electrical work. :/

dankhimself · Oct 7, 2011

Yea its more likely an 'open' then a short, a short arcs to ground, and open is just a loss of electrical path somewhere in the circuit, check the ground you did, go along all the wires in the starting circuit and make sure the conections are clean/tight. then go from there testing individual parts. Sounds to me that it is most likely a cheap fix, lets hope for the best!

killj0y · Oct 7, 2011

From the sounds of it you had to jump it, then it ran a short distance, possibly. From the small amount of charge in the battery left from the jump don't know how ong you let it sit with the booster cables though. After it dies no power at all? Yea sounds like a bad alternator cause even if the battery was dead it would run. Anyways get it tested before your battery really dies from no charge!

killj0y · Oct 7, 2011

Start with the simple then start hunting. For bad connections :icon_thumby:

snake · Oct 7, 2011

I was thinking bad cables- even if the alternator was charging perfectly, it won't matter if the power can't get back to the battery due to corrosion or bad connection. Try turning the headlights on, engine off, and have someone watch them while you wiggle everything. You'll find it soon enough.

killj0y · Oct 7, 2011

Or check for continuity

kimcrwbr1 · Oct 8, 2011

Replace the battery cables with good low resistence ones it sounds to me like you have internal corrosion you cant see. If you plan on keeping the truck especially with winter coming up. Marine grade cable ends and battery terminals work great and it makes it easy to add accessories down the road. batt+ to starter, batt+ to fuse block, batt- to engine, batt- to chassis and engine to chassis. Change or clean all the connections fully charge the battery, you can burn up the alternator or regulator charging a dead battery with the engine. If the battery is bad putting new cables on with a new battery is never a bad idea.

cubewhiz · Oct 8, 2011

Update:

I cleaned up the wires at the negative terminal and it started right up. I think that the corrosion that built up (I created quite a cloud with the wire brush) was causing the problem. I haven't driven it yet, but it started right up. BTW, where does the other end of this wire come from?

I also noticed that this little wire didn't have much left on the ends. When I unplugged it, the "Brake" and "Rear Antilock" lights both came on, so I assume it is brake related, but I'm not sure what it is.

lil_Blue_Ford · Oct 8, 2011

The first wire IIRC is your main frame ground. Should be anyway, should go down to a spot on the frame in front of the front tire where it's secured by a bolt. I wire-wheeled the frame and bolt then used a liberal dose of dielectric grease on the connection there to prevent corrosion.

The other wire, the one that affects the brake lights, is a ground for the brake circuit (not sure if anything else grounds through that one). Ideally you want it connected.

Electrical Issue?

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