89 f-150, 5.8. New battery, when the truck sits a couple of days the battery goes dead.i have had to put a shut-off on the ground, like i have on my antique car. The test i did twice. Unhooked ground. Pulled one fuse at a time ( door closed each time) put test light accross ground & it still lit like a short. This even happened with the old battery. Any suggestions where to look next. Thanks.

 

Try unhooking the alternator overnight. Sometime the regulator goes bad and it will back feed and let the battery drain.

 

If your wiring diagram shows 3 or 4 fuse links wired to the starter relay, remove them.

Does your test light go off?

Reconect the fuse links that dont turn the light on & see which accesories are not working.

 

Yep, Jimkinger is exactly right & one of the fuse links that I mentioned will be wired to the voltage regulator.

 

Thanks guys, i will try these suggestions

 

Still short,, i unhooked the big & small connector from altenator, unhooked small wire that looks like a fuse that is in the line, put test light accross ground on battery & it still lights, still a short. Any other suggestions.

 

A fusible link is a short piece of wire that is designed to break in the case of overload, just like a fuse. It will look like any other piece of wire but the jacket should say FUSE LINK or FUSIBLE LINK on it. On that truck, they should be on the passenger side, behind the battery running to the starter relay as 87 said.

They're easy to miss if you're looking for an actual fuse. These do not look the same. I'd recommend going back and looking for them.

 

That is the one i disconnected, the fuseable link behind the battery, thanks for your reply. Still had the short with all those wires disconnected.

 

That wire you disconnected was probably the PCM ground wire.

Like Virto sez you need to find the fuse links.

Try tracing the positive battery cable to the starter relay. There sould be a post on the relay with 3 or 4 small wires attached by a nut. Those are your fuse links & they power everything on your truck..

I have the factory wiring diagrams for all my Fords, but I dont have an 89 F-150 so i'm going from memory on this.

 

Ok, 87 xlt. I took off the 3 fusable links from the starter solenoid. There are 3 yellow links, one large, one medium & one small. I put them on the solenoid one at a time & tested for the short. The medium sized one came up with the short with my test light across the ground on the battery & cable. Any suggestion of what might be the problem. Thanks

 

maybe this will help.

 

I have seen the ASD Relay stick and cause this problem. Try pulling it
and see if it is your short. It should be on the left inner fender along with the fuel pump relay.

 

Tried to reply earlier, but the "submit reply" was MIA.

If you have the "charge & power distribution" wiring diagrams for your truck the rest of what you need to do is simple

1. Leave the one fuse link off & reconnect the other 2

2. Find something that isnt working.
Example: If the headlights are not working look at the wiring diagram & see which fuse link they are wired to.

3.See what else is wired to the same fuse link. One of those items is your problem. Any relays wired to the fuse link are a prime suspect for being stuck closed.

I have the factory wiring diagrams for all my Fords, but I dont have an 89 F-150 so I cant help you on that.

 

Yep a suck relay is a good possibility, especially since pulling all fuses did'nt find the problem.

 

BChance, do you happen to also have the charge/power distribution diagrams? Could you post them?