EEC relay fuse blows 3 sec after key turned to start position. | Ford Explorer Forums - Serious Explorations

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EEC relay fuse blows 3 sec after key turned to start position.

92EXPLORER92

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Joined
October 23, 2005
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City, State
Berlin N.H.
Year, Model & Trim Level
92 XL
Heres the problem, Got in the truck started it, went to get gas. Coming back from the gas station less than a mile Engine just dies!!! No sputter no shake cough nuthin, just died, seemingly electrical the way it just shut down. Had it looked at by a self proclaimed mechanic, said the fuel pump was gone. I had him put in a new one. Problem not solved. I began looking for the problem myself, found that the eec relay fuse under the hood was blown, switched it out, turned the key to start (heard the relay itself click) then EEC fuse blows again. Dont know where to begin with this problem I've done everything I think I can do as far as diagnosing the problem myself, I need help ANY will be appreciated

Thanks in Advance...
 



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So many possibilities. Everything in the EEC-IV engine management system gets power from that fuse. Not quite sure what the best way is to approach this. Sometimes I think the best thing would be to get a wiring diagram and unplug everything that gets power from the EEC relay. Turn the key on and see if the fuse blows. If it does, then the short is somewhere in the wiring harness. If it doesn't, then start making connections one at a time until it blows. Hopefull that will isolate the short to one sub-circuit and you can work accordingly.

However you approach it, you're going to want a good wiring diagram and you'll want to approach it logically so you can efectively narrow down where the short is. good luck.
 






EEC fuse blowing is fixed.....Thanks to all

Hey guys, thanks to all who posted suggestions to other people's problems on EEC 30 amp fuses blowing. I spent several hours on the Explorer Forum and from what each of you said, I was able to correctly trouble shoot and fiind the problem and to correct it in only a few minutes even though we used a fist full of fuses before we decided to make a jumper and use the cheaper 30 amp fuses.

Even though I didn't personally post my problem, I found several others who did and who appeared to have the same problem.

Again,, thanks.

allegro
 






unplug the 3-4 shift/lock up solenoid on the drivers side of the trans about half way back. it has 3 wires one of them is red and it is hot with the key on. the solenoid shorts and blows the eec fuse instantly. you can drive it without the solenoid plugged in, there just will not be any overdrive or lock-up convertor. i just wnet throught the same exact problem. drove me nuts!!
 






Many sensors get a signal of 12V+ from the PCM when the key is turned on, injectors, 02 sensors, etc..
It could in theory be a dead short anywhere in of this circuit. It is a solid red wire, goes everywhere!
 






It is helpful to remember that is a majority of cases involving high power items like solenoids , the PCM powers them up not by providing a 12+ to them, but by providing a ground for them (low power sensors may be a different matter). And there's quite a lot of those kind of things connected. I'd have to offer as a casual comment that the transmission seems to offer more than it's share of these kind of problems, and so endorse a good start being to unplug the connector harness there at least as one step in your process of elimination.

The posters you have heard from here in this thread are all very experienced auto electricial gurus (Mr. Shorty being my own particular "go to" genius electrical guru, right along with 410Fortune), and you can sense the collective "man this can be a potential bi%ch! of a problem to run down" feeling.

This is where scientific theory testing works best. change ONE thing at a time and test.

Oh and... (ahem) another spot where a breakout box could be priceless! ExplorerDMB are you listening ? <g> (I tease him about the value of breakout boxes).
 






Thats right Glac, there are 3 possible power sources sent fromthe PCM that can cause the EEC fuse to short.

The + red signal (acc on)
the grey/red signal return (sensors like the Canister purge are on this circuit)
the black/white which is the PCM - signal to sensors

and the light blue/orange that is also a + signal from the PCM (02 sensor pre heat and others)

All three of these are basically you turn the key the PCM send these signals, +, + and -, -
 






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I think I am going to annoint Dogfriend as the most useful poster for his diagrams and charts. Good job guy.
 






Glacier991 said:
Oh and... (ahem) another spot where a breakout box could be priceless! ExplorerDMB are you listening ? <g> (I tease him about the value of breakout boxes).


I hear ya I hear ya!

-Drew
 






EEC fuse blowing is fixed.....Thanks to all

Hey guys, thanks to all who posted suggestions to other people's problems on EEC 30 amp fuses blowing. I spent several hours on the Explorer Forum and from what each of you said, I was able to correctly trouble shoot and fiind the problem and to correct it in only a few minutes even though we used a fist full of fuses before we decided to make a jumper and use the cheaper 30 amp fuses.

Even though I didn't personally post my problem, I found several others who did and who appeared to have the same problem.

Again,, thanks.

allegro
What did u do to fix ur problem
 






December 10, 2005

was the last post to this thread. After 11 years I doubt you are going to got a reply from the original poster.

He only posted this one question and never returned. The Mystery remains... ..
 






December 10, 2005

was the last post to this thread. After 11 years I doubt you are going to got a reply from the original poster.

He only posted this one question and never returned. The Mystery remains... ..
Lol I figured it out finally damn 3-4 solenoid
 






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