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Discussion Starter #1
::LONG STORY::

So I started using my FJ less when I got a work car. It was only used on weekends, and even then we used my wife's car for the kids more often than
not. So it was not getting much use. The battery slowly drained over time (not able to use a trickle charger for street parking) and finally stopped starting. I replaced the battery and it worked fine for a few months of little use but then eventually that battery got low. (P.S. I have a winch and 2 sets of off road lights that also draw power)

Last winter, I got the jump pack and hooked it up (correctly) and I had sparks and the horn and lights pinned on until I removed the clamps. After that, it wouldn't start at all. No lights, no crank, nothing. I removed the battery, hooked it up in the garage to a trickle charger and slowly charged it. Took battery to two different stores and both said that it had enough power to start a vehicle and should work as needed. Re-installed battery and now I have lights on the dash lit up, but center console (radio, AC, etc) no power. When I go to turn it over, nothing. No crank, no clicks, nothing at all. Headlights still work, lock/unlock via remote still work, dome lights work, but nothing on the center console.

I checked all fuses (under the hood and under the dash) and I had 4 fuses blown under the hood. Replaced all of those and still same result. I should add I have an aftermarket VTP (Vehicle Theft Protection) alarm that installed by dealership. This alarm has a key pad attached to the center console that requires a pin to start the vehicle, that is also not lighting up. (P.S. I have a winch and 2 sets of off road lights that also draw some power I assume)

So before I have it towed to the shop and tell them this story and have them charge me a million dollars to diagnose the problem, I thought I would come to you guys/gals for help first in case there is something I haven't thought of yet. Any help is much appreciated!

Cheers!
 

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Dont be depressed. I'm in the exact same situation as you. Over the past 3 months I neglected my battery. Tried to start the Cruiser on Monday and nothing. Dead battery only measuring 3 volts. Slowly charged it to 12.4 volts but it doesn't have enough AMPs to turn the engine over.

I'm going to guess that the shops you took your battery to did not have the capability to measure amperage. Time to purchase a new battery!
 

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The 120 amp alternator fuse is a likely culprit. If your windshield wipers activated unexpectedly, that's often a sign of this fuse blowing. Look very carefully at the fuse, as this is a hard break to see. Remove the clear plastic cover on it if you need to.

Your box will look a little different. I hacked mine up to "future proof" it should I need to make this repair again on the trail.

If this fuse is blown, you will have to disassemble the fuse box to unbolt it. It's a pain in the ass to disassemble the box, but the fuse is only like $4.

A good thread on the replacement, if this is your problem: 120 Amp fuse replacement





 

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Discussion Starter #5
Thank you for all of your input. I remember looking at the 120A fuse but I don't recall off the top of my head if it was blown. I will check it again after work and run through that thread to see how to replace it if that is the problem. You guys rock!
 

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I think you provided the two key bits information required for initial diagnosis:

1. "I got the jump pack and hooked it up (correctly) and I had sparks and the horn and lights pinned on until I removed the clamps. After that, it wouldn't start at all. No lights, no crank, nothing."

2. "I checked all fuses (under the hood and under the dash) and I had 4 fuses blown under the hood."

Despite what you may think, you hooked the jump pack with reversed polarity. The pack probably couldn't provide enough current to blow the 120A alternator fuse, but did blow the lower-amperage fuses on multiple other circuits.

Tell us specifically which fuses were blown in the engine bay fuse panel, and we may be able to provide some guidance on the next steps. Be warned that applying reverse polarity to the vehicle's electrical system with something that can supply a large surge current (like a jump pack) can have very serious consequences.

(The 120A fuse is in the alternator output line. If it is blown the vehicle will start and run just fine, it's just that the alternator won't charge the battery.)
 

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Discussion Starter #8
I think you provided the two key bits information required for initial diagnosis:

1. "I got the jump pack and hooked it up (correctly) and I had sparks and the horn and lights pinned on until I removed the clamps. After that, it wouldn't start at all. No lights, no crank, nothing."

2. "I checked all fuses (under the hood and under the dash) and I had 4 fuses blown under the hood."

Despite what you may think, you hooked the jump pack with reversed polarity. The pack probably couldn't provide enough current to blow the 120A alternator fuse, but did blow the lower-amperage fuses on multiple other circuits.

Tell us specifically which fuses were blown in the engine bay fuse panel, and we may be able to provide some guidance on the next steps. Be warned that applying reverse polarity to the vehicle's electrical system with something that can supply a large surge current (like a jump pack) can have very serious consequences.

(The 120A fuse is in the alternator output line. If it is blown the vehicle will start and run just fine, it's just that the alternator won't charge the battery.)
To the best of my knowledge, these were the 4 fuses I burned out:
(1) 10
(1) 15
(2) 20
1133334
 

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To the best of my knowledge, these were the 4 fuses I burned out:
(1) 10
(1) 15
(2) 20
1133334
If you can recall, which circuits?
 
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Discussion Starter #11
If you can recall, which circuits?
So based on this diagram I think it was:

F23 (ETCS)
F26: (Towing)
F25 or F27: DR/L CK or Radio No.2

F14: Defog

1133335


But based on this diagram F14 shows a 30A. The one in my fuse box was a 20. And im leaning more towards the second 20A being F27 not F25.
 

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A strange mix.
 

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My '13 does have a 30 for defog. I don't know enough about the FJ electrical system to understand why the fuses that failed did. Most DC electronics I worked on were protected by a circuit or diode for reverse polarity connection.

From my '13

IMG_0656.JPG

IMG_0657.JPG
 

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My '13 does have a 30 for defog. I don't know enough about the FJ electrical system to understand why the fuses that failed did. Most DC electronics I worked on were protected by a circuit or diode for reverse polarity connection.

From my '13

View attachment 1133347

View attachment 1133346
Generally there is no reverse polarity protection in any automotive systems, as the cost of adding many 10A, 20A, and 30A diodes and their heat sinks would be totally cost-prohibitive. Also they'd introduce ~0.3-0.5 volt voltage drop in every circuit they fed.

The assumption is that no one is going to be careless enough to reverse-connect jumper cables or 'jump packs'.
 

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Generally there is no reverse polarity protection in any automotive systems, as the cost of adding many 10A, 20A, and 30A diodes and their heat sinks would be totally cost-prohibitive. Also they'd introduce ~0.3-0.5 volt voltage drop in every circuit they fed.

The assumption is that no one is going to be careless enough to reverse-connect jumper cables or 'jump packs'.
Thanks, yes, I didn't think of the current draw.

Really interested to see where this thread goes. I learn something new all the time. :)
 

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OK, let’s review what we know:
1. Probable reverse-polarity jump-start event.
2. Headlights and horn latched on as soon as jump power was applied.
3. Multiple blown fuses in engine bay fuse block.
4. Most interior circuits appear to be live, but not center stack.
5. Engine won’t crank.
6. Aftermarket theft-protection system.

First, let’s try what (hopefully) is the easy part - the 'no power to center stack' problem. With luck, you have missed a blown fuse, and have not toasted the Body ECU or other $$$ components. The aftermarket theft-prevention system will become a prime suspect if we can get all the other power issues resolved, but still don't get spark or fuel pressure.

Go back and re-check ALL the fuses in BOTH fuse blocks, paying particular attention to the following fuses. You should physically pull them from the fuse block for inspection and testing:
RADIO-1
ACC
IG1
ECU-B
HEATER

Questions:
1. What year FJ is this?
2. Can you read electrical schematics?
3. Are you checking fuses visually, or with an ohm meter?
4. Does he HVAC blower work?
5. Do the brake lights work?
 

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Discussion Starter #17
Ok I got home last night and realized the 120A fuse was blown. Also I told you the wrong blown fuses earlier. It was the F17 (*10) in the above diagram not the F14 (Defog) fuse. The rest of the previously mentioned ones were correct.

To answer your questions:

1. its a 2007 FJ
2. No I can't read electrical schematics.
3. I am visually looking at them not testing with OHM meter.
4. HVAC blower did not work either.
5. I will check brake lights when I get home from work.
 

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Ok I got home last night and realized the 120A fuse was blown. Also I told you the wrong blown fuses earlier. It was the F17 (*10) in the above diagram not the F14 (Defog) fuse. The rest of the previously mentioned ones were correct.

To answer your questions:

1. its a 2007 FJ
2. No I can't read electrical schematics.
3. I am visually looking at them not testing with OHM meter.
4. HVAC blower did not work either.
5. I will check brake lights when I get home from work.
OK, the blown 120A fuse ABSOLUTELY confirms that you incorrectly connected the jump-pack. Replacing the 120A fuse is a bit of a chore, review the earlier DIY info in post #4 and see if that is something you would feel comfortable doing.

If you don't have a multimeter and aren't familiar with reading schematics, it may be best to have the vehicle flat-bedded to a dealer or automotive electrical speciality shop for further diagnostics and repair.
 

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The 120A fuse is in the alternator output line. If it is blown the vehicle will start and run just fine, it's just that the alternator won't charge the battery.
That is incorrect. Mine ran fine until stopped, and with the solar panel the battery stayed topped off, but a blown 120A alternator fuse results in a no-crank / no-start condition on the FJ, at least on the 2007.
 

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That is incorrect. Mine ran fine until stopped, and with the solar panel the battery stayed topped off, but a blown 120A alternator fuse results in a no-crank / no-start condition on the FJ, at least on the 2007.
The only function of the 120A fuse is to protect the alternator output wiring and the alternator from an overcurrent condition. This fuse is located very close to the battery, showing that Toyota is trying to protect the wiring and alternator from an overcurrent event originating at the battery (battery installed backwards, or jumper cable installed backwards).

Any type of catastrophic electrical system fault that was severe enough to blow the 120A alternator fuse is almost certainly going to damage other parts of the electrical system, and THAT is what will create the no-crank/no-start condition.

That's exactly what happened to the OP who started this thread.

This is very easy to demonstrate by simply disconnecting the alternator output wire at the alternator terminal, and starting the engine ... it will run fine as long as the battery can supply enough current to run the fuel injection and ignition systems, but the BATT light on the instrument panel will be on because the battery is not being charged.

Note the location of the 120A fuse, connected directly between the alternator's output line (block of six diodes) and the + side of the battery ... it's not tied into any other part of the electrical system that would have any affect on cranking or starting.

Charging system schematic.JPG
 
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