Deep Trouble. Electrical System Eff Up

[simple]

Hey guys,

I sent a PM to J.A. But in the meantime I wanted to see if I could query any other electrical geniuses. I was wiring up some puddle lights on my side mirrors and was using J.A.'s method that he used for his footwell lighting mod, meaning I tapped the positive wires on the Dome light Relay wire and the negative on the ILE light wire. I was doing some final checks before completing the wiring and checking I had the correct puddle light wires going to the right vehicle wires. We'll both live wires I have running from the car touched and there was a tiny bit of smoke that came off. I separated them and finished the wiring. But the puddle lights failed to work. Infact not one single thing works now. The car won't even crank.

Boy did I Eff up. I checked some random fuses but not really sure what I should check or what. Does anybody have any ideas?

Thanks

 

[Trumpet]

Start methodically checking the fuses in both the dash and engine fuse boxes. Check visually and with a ohm meter or continuity tested. Sometimes they look ok even when blown.

 

[simple]

Solved, J.A. And Trumpet nailed it. It was the dome fuse, replaced and now I have a car. Makes complete sense don't know why I didn't think of it.

 

[AuSeeker]

Glad to hear you got it fixed...BUT let this be a lesson to you and others to disconnect the battery when doing even what seems to be simple electric work/additional wiring/re-wiring on modern vehicles, shorting out the wrong wire/circuit and you can fry CPUs and other major components at a very expensive cost!!

 

[TowMeOut]

OK.....I must have missed something. How does a smoked dome light fuse keep your truck from starting?? Is there more to this story?

 

[simple]

OK.....I must have missed something. How does a smoked dome light fuse keep your truck from starting?? Is there more to this story?

That's why I didn't even think of checking the dome light fuse. I was looking for like 'entire car' or something 'really important' fuse. But sure enough the dome fuse was completely blown. When I plugged a new 10a fuse in, my car came alive. When I tested that the car would start, I half expected my odometer to have gone to 0, lol. But to answer your question, yes, the dome fuse completely killed my car's electrical system, and I don't know why.

 

[Ventil8]

J.A has some killer electrical skills. I've bookmarked his website since i found this forum many years ago.

 

[Phils4th]

OK.....I must have missed something. How does a smoked dome light fuse keep your truck from starting?? Is there more to this story?

It's an electrical buss. The dome light is just the most popular/noticeable circuit.

 

[TowMeOut]

Yeah...I get there are multiple main buss lines in the fuse panel. Each one has a higher amperage fuse that services that separate line. But...he doesn't mention blowing/replacing any of those, just the dome light fuse. Just for giggles I just walked out and pulled the 10A fuse labeled "dome" in the panel under the hood (right next to the 20A radio fuse). I hopped in the driver's seat and fired the truck right up. No warning lights, no problems, everything else but the dome light worked fine.

So, does the 4th Gen have some auto-resetting circuit breakers hiding out in there somewhere too? Could you overload the circuit with the short, smoking the dome light fuse but also disrupting other power? Then, while you're fumbling around under the dash/hood this thing resets?? Nothing obvious jumped out at me looking in either panel, just relays and fuses. Or....does it have some factory/aftermarket anti-theft starter disable that killed everything due to the overload??

I spent about half my military career doing electronics maintenance. I can find my way around a schematic and some test equipment. We called these kinds of problems CWC (cleared while checking) or more likely FM (f-in magic). But when the whole electrical system of the vehicle dies because of a 10A fuse there's something strange going on...

On my way home I found a friend of mine in the Home Depot parking lot with a car that was DOA. It was an old Ford Galaxy with a solenoid bolted to the fender running straight to the starter. All we got was a good "click" of the solenoid but the starter didn't make a peep. We tried the redneck approach bypassing the solenoid by putting the positive of the jumper cables straight to the starter input terminal. We got some sparks but it didn't budge. It's a pretty straightforward system to troubleshoot. However both battery connections were the "emergency" replacement type and pretty corroded. The main ground connection was cruddy going to the body panel with no additional strap going to the engine block. Oh, and the battery was like 4 years old which in FL is about the max lifespan due to the heat and salt (but it still registered 12.6v, not bad). I ran him up to the auto parts store to grab a new battery and his wife was coming to shuttle him home later. I'm curious what the "fix" will be for his problem.