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BluntMomma
06-12-2006, 05:57 PM
hey all got a problem we need some help with! My truck has been draining the battery...we've changed it twice, and just realized that with no key in the ignition, and ignition off, even with the ignition switch out, for some reason, the truck is continually giving power to the high pressure fuel pump. Which leads us to beleive it is a wiring problem, possibly the computer? You take the negative battery cable off, and then re-attach it, and you can hear the high pressure fuel pump prime itself. So obviously there is some power being sent around in the vehicle (may be powering more than just the pump, but the windows and locks don't work without the key in the on position)

Does anyone have any ideas?

adrock
06-12-2006, 07:02 PM
relay shorted?

BluntMomma
06-12-2006, 07:48 PM
Thanx Adrock, but yeah, we just tried the one off of my other Bronco onto this one, and its still happening. Only two other possibilities I can think of, and thats the computer or there's a short somewhere in the wiring. Damn. Luckily, we bought a used computer awhile back from an 89 EB edition from Chilliwack Pick a part. So I guess we'll try that. If that doesn't work, Sean and I will both have white hair or be bald from pulling it out! Friggin hellllllll!!!

BluntMomma
06-13-2006, 10:12 AM
Ok so it wasn't the computer, either! Me thinks its time to take it in to get analyzed. Mother#@%$@*%#!!!!!!

lizard
06-13-2006, 10:24 AM
disconnect it, put in a manual switch, plus is, its an anti theft thing.

BluntMomma
06-13-2006, 01:10 PM
Theres a plan! I'll see what Sean sez...but I agree. Thanks!

Hyenuf
06-13-2006, 01:18 PM
This sounds familiar!!


Check the ignition switch itself.... There may be a short between two terminals within the switch itself or the plug attatching to it!

Also check the back side of the fuse/ relay panel..... may be a short in there as well.

Kinda hard to diagnose without seeing the truck... hope this helps

OldEnuff
06-13-2006, 07:36 PM
Broncos are famous for "mystery shorts/battery drains".

They often get shorts from one wire to another in a wiring bundle.
Almost impossible to diagnose.

However what you can do is start removing one fuse at a time and see if the fuel pump still powers up.

If it does then put the fuse back and go to the next one.

Hopefully you can narrow it down to which circuit is leaking power.

Hope this helps

BluntMomma
06-19-2006, 03:59 PM
Thanks Buckin Bronco...Imma try that! What the hell, cuz I can't find any other way to diagnose the bitch!

StinkFinger
06-19-2006, 04:28 PM
Broncos are famous for "mystery shorts/battery drains".

They often get shorts from one wire to another in a wiring bundle.
Almost impossible to diagnose.

However what you can do is start removing one fuse at a time and see if the fuel pump still powers up.

If it does then put the fuse back and go to the next one.

Hopefully you can narrow it down to which circuit is leaking power.

Hope this helps


This is an exelent way to diagnose electrick works good to if you disconect a battery lead and conect a meter in between the lead ant the battery terminal then start pulling the fuses if there is a change in the meter you have found your bad cirket

In The Zone
06-19-2006, 05:24 PM
If the pump is running all the time check your key on voltage and probe the Appropriate wire from the ecc harness you should have a 12v signal to activate the fuelpump relay

should be no voltage with key off

then check voltage from relay to inertia switch again should be no volts with key off

if u have power there then the short is between your ignition switch and relay probally as stated a wire bundle corroding and making contact
easiest solution then rip the harness apart and start tracing wires it is really not difficult just do a section at a atime un wrap

if left it could start a engine fire eventually... a fuse iwill not protect the circut in a instance such as this

StinkFinger
06-19-2006, 05:39 PM
This is an exelent way to diagnose electrick works good to if you disconect a battery lead and conect a meter in between the lead ant the battery terminal then start pulling the fuses if there is a change in the meter you have found your bad wiering

Jroc
06-19-2006, 10:09 PM
theirs a pack of relays by the air box , get the EEC one $17 fixed my prob with that, but its an 89 bronco so what do i know?

Always broke
06-21-2006, 10:34 AM
Do what Stinky said but use a test light instead then its a visual thing can see easily just put it between the battery and the ground and keep pulling fuses until the light goes out , also the Bronco's a famous for bad relays go to pick a part and get a whole bunch of them and try changing them all should be really cheap.[cheers]

Pudge
06-21-2006, 10:43 AM
[stupid] Go with Todd/Stinky's method. Todd told me about that method when I was having battery draw issues, and it was a cheap simple way to figure it out. And it worked too:D

[cheers]

In The Zone
06-21-2006, 10:57 AM
Sounds like u will get it figured out these guys know their shit

invest in some oem schematics or aquire them online if ya need em
mandatory for newer shit.