ok, i just aquired a 1997 f150 w/ v6 and auto tranny that was abandoned at my job. the wiring seems screwy to me. It has the normal cables going to the battery, but also has a thick copper wire going to each battery terminal going from battery to connection directly behind it on the firewall that are held in place by the normal battery clamps. the previous owner said he has replaced the battery and alternator (and they both look new), but that the battery is not charging. I took the battery to auto zone to charge overnight, and it tested good the next day. i installed and it wouldn't start (no sounds from starter). It when i hook up all four leads to battery, the light under hood lights up, and door dinger sounds, but i get nothing from the ignition, or even sound from the radio. before i jump to conclusion that its a bad starter, i'm thinking that since i know there is an electrical problem that perhaps the starter's not gettting any juice. Also, i believe it is the fusible link between the battery and alternator is taped up to hold in place, could this be a source of problems? Also, i'm unfamiliar with the batter saver relay. What does this control, and is that something that might need to be looked at?
I was told to clean the electrical connections on another forum, but haven't had many responses. When i find my dad's multimeter, i'll check out the voltage levels. here's some pictures so you'll have a better idea of what i'm talking about.

these are the extra wires i was talking about (one terminal unconnected).



this is where the extra wires connect.


this is the taped up fusible link


hope anyone can give me any advice. i'm not a pro at auto repair, but have done my fair share. electrical problems are a pain in my backside though.
brandon

 

That taped up fuseable link is actually a Mega Fuse. Start by replacing it. There should be one cable coming from the POS post of the battery to the terminal on the switch on the firewall with the two large red cables. The other terminal on the switch should have a smaller gauge wire going to the solenoid on the starter. From the terminal with those two red cables there should be a cable from the alternator to charge the battery. The two red cables go to the Mega fuses. The top mega fuse goes to the main fuse box called the battery Junction box. It is located on the driver side fender. The bottom mega fuse feeds the starter and is always hot.


.

 

cool... that makes sense. does the alternator assist in starting the vehicle? i thought it was solely the battery to start and then the alternator charges the battery. I was told maybe the alternator got messed up when the battery drained too low. but i don't think that would be a problem for starting the engine.

 

The alternator is there to provide current when the engine is running. It should be powerful enough to supply all the electrical needs and have enough left over to recharge the battery.

Regards

Jean Marc Chartier

 

those battery cables look pretty new as well, but look like a generic fit type, that may not have all the factory connections needed. You really need to put a metal "tip" on the end of those wires to safely secure them to the battery terminals

 

The first thing that I would do is get rid of those 2 add on cables from the battery. Then replace the mega fuse and make sure the alternator power wire is good from the alt to the mega fuse. The small wire to the solenoid is the one that energizes it when you turn the key to start. Check the other battery wire and make sure it has a good ground.

 

Sorry I didn't notice this before the previous post. The ground wire from the battery to the body has been shorting out to the positive cable and to the post on the solenoid that goes to the starter. You can repair that one by using a large terminal and mount it to the battery bolt on the negative battery terminal and just reroute so it doesn't rub on the positive cables or posts.

 

RebColonel,
i'm not sure if i get the gist of your second post. I don't see any visual damage to the wire. are the cables running to the wrong place? I'm ok with cars, but electrical systems are my kryptonite. i need to find where the cables with the clamps are running. do i need for the positive cable to run to the terminal on the firewall, and the negative to the bolt next to it? or does the positive need to run to the starter? I'm going to follow your advice on your first post, i'm hoping i can wrap my head around your meaning of the second post. like i said electrical systems are not my strong suit... hopefully i'll learn more after this endevour.

also, where is the switch in the cab for the auto fuel pump shut off? i know a customer backed into the truck while it was parked and it may need resetting.
thanks,
brandon

 

Ok I'll try to make this simple. The added on wire on the negative terminal needs to be connected more securely to the battery terminal, it runs to the body as a ground wire up and to the right of the solenoid. Just make sure it doesn't rub on any positive cabble or post. The positive battery cable goes to the right hand post on the solenoid. I can't tell where the other added on cable goes, but remove it.

 

I think the added on positive cable(the one with the bare end) does go down to the starter. I can't tell from the picture.

 

ok, i replaced the mega fuse and still wouldn't start. I found the way the battery is wired the cables w/ the clamps both go directly to the starter. the add on positive cable goes to the terminal on firewall, and add on negative goes to the body ground.
i accidently touched the terminal on firewall with socket and drew sparks. did i cause any damage? or is something wrong?
Should i remove the battery cables going to the starter?
Also, in the fusebox on the driver's side, should all fuses be facing the same direction, or does that matter? And the very first space in the middle row there is a wire jumping the bridge. From the manual this looks like it is for trailer brakes which i don't think it has as there is no hitch. I didn't get to look too closely at those fuses though. Texas is hot and i felt like i was going to pass out so i called it quits.
Also, battery voltage was 12.69 before i connected cables to the battery. after i connected it, it dropped to 12.54. i assume something is causing a draw, but don't know if the onboard computer will draw that much power. if that helps with anything cool.
thanks,
brandon