Calling all electrical gurus

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This past winter I had lots of issues with my butt warmer seat heaters blowing fuses; now you may say this is not related but in doing research over all my track downs I went thru all 3 of my fuse box in the vehicle (now it depends on your year how many and where they are).

the biggest thing is that you said all the lights went out (radio /dash etc) then you should focus on main power supply connections; like someone noted before rodents seem to love chewing on the plastic wrapped wires; because you had a whole lot of stuff going on (radio lights etc) it has to be a main power source issue. most of the items are isolated so if a particular item breaks the rest still works; example if your stereo craps out the vehicle should still run. I think you are on the right track with alternator etc but follow up that first. when checking the alternator did you check all of those connections??
 
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he is one of the fuse diagrams
 
Corrosion in the bus bars between the battery terminals and the fusible links has given me lots of electrical headaches in my 2000. I highly recommend pulling those connections apart and cleaning them. Mine were corroded on the underside of the bus bars, so it was missed on common inspection. It's also a good opportunity to add an extra fusible link and run your amplifiers and other accessories from it instead of connecting to the positive battery terminal.
 
it has to be something like that above due to the fact everything went out; if it was one particular item then you would be tracing fuses etc
 
** Update **

I was going to provide an update this weekend saying everything is now a ok and chalk everything up to a loose connection on the battery. Since August I have put about 1,000 miles with no issues of any kind. Including several miles of off roading at Logan's Run with Olde North State Cruisers. However, I am glad I did not do so because the "issue" has come back. This Sunday I was parking the LX and put the AHC in H mode. When that happened the lights all lit up and everything shut off. It was kinda like the LX did not have enough electricity to continue, at the time the RPM was at idle.

However, it started right back up again and there was zero issues the rest of the day as well as on Monday. However, today when I pulled into my driveway I had a feeling that the electricity was "low" again. I know this sounds crazy, but I knew something was up because I can hear it in my stereo first. Speakers make a whining noise and actually cut out a bit. So while parked I decided to see if I can recreate what I experienced on Sunday. So I raise the AHC back to H mode and again all the dash lights light up and you can tell there was a power issue. The LX was at idle this whole time. So I switch between N and H about 3-4 times and each time the same thing happens, however the engine never cuts off. When I cut the ignition the battery was essentially dead. Got my volt meter and the reading on the battery terminals is 12.3 V. I thought it was a little low but enough to start it back up. However, nothing works when the LX is off. So I grab my jump box and the LX fired right up. Drove it around the neighborhood and when I got back and turned in off the battery was dead.


So to me this obviously screams a new battery is needed, but I have never ever had a battery out and act like this. Usually, it has been extremely clear when a battery has gone dead. Now I have never had a battery go out on a 100 series, so I am curious if ANYONE has experienced something like this when their battery went out? I don't know if this is really a testament to Toyota Engineering making this rig last so long on a bad battery, as the original symptoms were experienced more than a month ago, but have been non existent until now. Also for whats its worth, the battery currently in there has a sticker of 11/11, so I assume that means it was installed Nov of 2011. However, I don't know this for sure as it was installed by the previous owner. As always, thanks guys for your insight and help.
 
It sounds like you had a marginal battery and a dying alternator. It is my understanding that when the vehicle is running that the battery is being charged and the vechicle runs off the alternator. I would suspect it is a combination of the both.
 
The vehicle does NOT run off the alternator - it runs off the battery. The alternator charges the battery.

OP you are right to suspect the battery itself. Swap it out. Alternatively I would consider the ground system from the battery to chassis and engine - Is it loose or degraded?
 
You have a voltmeter so testing the battery and alternator separately is very easy. I would check both (just because the alternator is bad does not mean it won't need a new battery as well. A poor or intermittently failing alternator will wear out a borderline/old battery faster by making it cycle more deeply than it should). I have to say that the alternator does not just recharge the battery--that's simply not correct. Normal electrical function in a modern vehicle will not occur with a good battery and a failing alternator, as high amperage devices (such as AHC pumps, high watt amplifiers with the bass or volume turned up) draw a lot of current and rely on the higher voltage you get with normal alternator function.

I think one of the most common mistakes DIY mechanics make is simply throwing a new battery in a car or truck when something like this happens. If the alternator is failing but not dead a new battery can usually compensate for a while, but in a month or two (or sooner) the same problems will recur.
 
RobRed said:
The vehicle does NOT run off the alternator - it runs off the battery. The alternator charges the battery.

OP you are right to suspect the battery itself. Swap it out. Alternatively I would consider the ground system from the battery to chassis and engine - Is it loose or degraded?
Click to expand...

Well much to my surprise the LX started up this morning without the jump box. Now it was obvious that battery was very low because it barely had enough power to unlock the doors, but when I turned the key it fired right up. I kept an eye on the dummy volt meter on the dash and It would drop when at idle, but then go back up to 3/4 when I was moving. When I got to the office I put it in H with no issue and then turned it off. Then I tried to restart it and it acted like it had full power again with no issues at all. A couple of weeks back I checked the ground and it was fine, not loose or corroded in anyway. Though I am still thinking battery at this point. I am curious how would I go about testing the alternator? In the past I have just removed them and taken them to a local shop for testing. Originally, I did a dummy test where I took the volt reading on the battery when it was not running. Then drove it around a bit and retested the volts on the battery again (not running of course). At that time, the battery was clearly taking a charge. Sorry for such a stupid question.

Naturally, all of this is happening during the middle of the work week where my time is extremely limited. Most likely I will not really be able to jump into this until Friday at the earliest. Thanks guys.
 
I have a couple of more random thoughts with this additional info.

-A lead acid battery that is fully charged, will be about 12.7-12.8 volts. If yours is less than that, it is either failing or not being charged. 12.3 means the state of charge (SOC) is about 50% roughly. If your battery has caps, look inside and see if all the cells have the right level of electrolyte.

-It would be worth putting the battery on a smart charger overnight and see if it still has the ability to recover to a higher voltage.

-When you start your truck and run for a bit, what is the voltage measured right at the battery terminals? It should be 13.9-14.0 if it isn't, and you are certain of all of the connections in the charging circuit, your alternator is bad.

-It is very strange that the AHC seems to make a difference. Is that a high power circuit? It would make me look for wires that chafe or move when you raise the AHC.

-The fact that it is intermittent still suggests a bad or loose connection. So again, look at all of it with special attention to the connections near the battery, the fusible links, and the ground connection from the battery back to the motor.

-You can take voltage measurements in seconds. Battery resting voltage, and engine on voltage at the battery terminals will tell the tale.
 
I'd say check your grounds to the engine block and chassis and the. Remove the battery and the alternator and have an independent shop check both. If you have a standalone charger I'd charge the battery separate from the vehicle before taking it to get it checked. Make sure it reads 12.6vdc. I'd do these first because why not check the starting point of your electrical before going any deeper. If those are good then you KNOW it's something else. Those items are the most likely to fail though. Also either a bad alternator or bad battery can take out the other as well. Both the alternator and the battery can cause the symptoms your seeing.
 
LockedNLoaded said:
Well much to my surprise the LX started up this morning without the jump box. Now it was obvious that battery was very low because it barely had enough power to unlock the doors, but when I turned the key it fired right up. I kept an eye on the dummy volt meter on the dash and It would drop when at idle, but then go back up to 3/4 when I was moving. When I got to the office I put it in H with no issue and then turned it off. Then I tried to restart it and it acted like it had full power again with no issues at all. A couple of weeks back I checked the ground and it was fine, not loose or corroded in anyway. Though I am still thinking battery at this point. I am curious how would I go about testing the alternator? In the past I have just removed them and taken them to a local shop for testing. Originally, I did a dummy test where I took the volt reading on the battery when it was not running. Then drove it around a bit and retested the volts on the battery again (not running of course). At that time, the battery was clearly taking a charge. Sorry for such a stupid question.

Naturally, all of this is happening during the middle of the work week where my time is extremely limited. Most likely I will not really be able to jump into this until Friday at the earliest. Thanks guys.
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Not sure if you have the charging cct FSM so here's a copy, probably better than me regurgitating stuff. A couple of points that have already been touched on. If you have a standard wet cell battery the temperature corrected SG is the way to check the charge and health of each cell and voltage readings taken under no load are of limited value. Voltage and current readings from your battery and alternator under load will likely reveal much more. If you have access to a smart charger your battery would likely benefit from a good charge, and if you can then check SG even better. Final points; with the engine running and alternator dc output in the specified ranges your battery actually presents itself as a load to the charging system, just a reserve, voltage smoothing storage device. And if you do the current check under load ensure your multimeter can handle the 30+ amps, many are only good to 10 amps.
 

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My bet is a a bad ground. Combo meter and radio share the same ground located under the left kick panel. They also share a junction block ground tapped up in the harness I believe behind the drivers side dash. 60's are really bad about this but not unheard of in a 100 series. I'd check the kick panel ground first cause it ties into the ECU as well. The fact your having power draw issues on the radio and combo meter and lights makes me thing is a ground.
 
Update-- I thought I would post the solution to this problem to help others down the line if they search and find this thread. I waited several months before posting this because I wanted to make sure that this issue is 100% fixed and it is. The whole entire issue was a bad battery believe it or not. In all my life I have never had a bad battery give these types of issues in the past. Normally it the past its been very clear when a battery goes bad, but not in this case. I certainly appreciate everyone's suggestions and insights, but in the end the solution was to just change the F-ing battery. Did so back in Oct and have not had any issues since.
 
LockedNLoaded said:
...All things considered this is a stock unmolested LX that I bought from a CEO, so it never ever saw any off roading at all...
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#1...I'm glad you identified and fixed the issue.

#2...The bit in red above is not an absolute, especially in my case. ;)

Steve
 
We're so quick to jump to everything little tiny random thing it could be...and turns out to be a bad battery. I was sticking with alternator, o well.
 
This scenario happened to me today. I was cruising along when my radio cut out. Immediately looking down I realized that the entire dash did a reboot. Nav, lights, etc all did the self check. No change in driving, the LX continued on.

When I arrived at my clients location I noticed the remote was not locking the door. Tried to start the engine and it was a no go. Right now I'm waiting on a buddy to help me test it out. I picked up the only avail alternator in the tri-county area just in case but I'm crossing my fingers it's the battery like above. All I'm getting is the door ajar sign, all other electronics are completely off. I'm also crossing my fingers it's not ignition cylinder related.
 
A quick stop at an auto parts store can help with these situations. They can do a quick test in situ, in the parking lot to help give you an idea.

Further testing can be done out of car, but to get a general idea you can have them test in their parking lot and know something in all of 5 minutes.
 
Mine was a Nevada truck Las Vegas great for no rust hard on rubber, battery and paint. I checked my battery last fall needed distilled water filled it up but since it was 3-4 years old I just had a new OEM Toyota battery installed for $100. Now I don't have to jack with any battery issues. Maybe I over maintain but half the reason I belong to Mud is to ID potential problems and fix them ahead of time.
 
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