Short draining battery

[sumncguy]

I bought 90 ranger with a 2.9l. The battery kept dying. It tested marginal so I replaced it.
However the new replacementbattery went dead. I broke out the test light. ..testing with the test light between the negative cable and negative post on the battery I started pulling fuses.

The light went out when I pulled the 30a fuse in the power distribution box. EEC Control.

A few diagrams, if Im reading them right, indicate that that circuit is always hot.

If I pull this fuse the battery holds the charge. Ive been pulling the fuse when the truck is parked.

I guess the question is, what is the next step to trouble shoot this circuit ?

 

[RonD]

Radio and EEC KAM(keep alive memory) should always have power, and keyless entry on later model vehicles.
But this can't drain a battery, it would last over a year, even longer if new

That 30amp fuse should be power for the EEC Relay to pass on, when relay closes it powers fuel injectors, spark and the computer(EEC).
EEC relay should be OPEN when key is off, so no power draw
Check(pull out) that relay and see if power draw goes away, with 30amp fuse in place

With key still off put relay back in and listen for a "click", if you hear a click then ignition switch is Closing that relay when it shouldn't be, so ignition switch, under steering column, could be loose/bad.
If you do not hear a click then use test light to check if a fuel injector has power, any injector wire is fine and either wire, ground test light to battery or engine and touch it to any fuel injector wire
If there is power at an injector then replace relay

 

[sumncguy]

negative Battery cable.

about ten inches of insulation missing from cable down where its grounded to the block,

 

[Doofy]

Why would a grounded neg. Battery cable make any difference? That is its job.

 

[adsm08]

I agree with Doofy.

IME the only thing on a truck that old that an kill the battery in just a few hours with a parasitic draw is the alternator.