Toyota FJ Cruiser Forum banner

911!! Electircal gremlin stikes...every stopped working. Please advise

2K views 11 replies 5 participants last post by  diamatrix1970 
#1 ·
Facts:
air bag light came on at 5pm today
at the same time the follow:
-turn signals don't work
-speedometer doesn't work
-battery isn't charging...its draining as I drive
-fan blower doesn't work
-rear defrost doesn't respond

everything else works
I checked all fuses they are fine.
disconnected battery for 10 min...nothing

PO had a powered sub and back up camera that the dealer removed.

any initial thoughts and directions?

thanks in advance
 
#2 ·
Electrical headache!! Need some experienced help

put this in the tech forum....need some advice quickly

Facts:
air bag light came on at 5pm today
at the same time the follow:
-turn signals don't work
-speedometer doesn't work
-battery isn't charging...its draining as I drive
-fan blower doesn't work
-rear defrost doesn't respond

everything else works
I checked all fuses they are fine.
disconnected battery for 10 min...nothing

PO had a powered sub and back up camera that the dealer removed.

any initial thoughts and directions?

thanks in advance
 
#5 ·
Check to see if the alternator has output to the battery... Also, check for AC Voltage bleed over by changing the scale on the multimeter to read AC Volts when connected to the battery... Having AC Output can cause all sorts of weird faults and often is over looked. It means the voltage rectifier is fault in the Alternator.
 
#7 ·
First, what year is your FJ, and how many miles on the odometer?

Do you know if the alternator has ever been overhauled or replaced?

How old is the battery? If it's not a sealed battery, have you checked the electrolyte level in each cell?

When you say "battery is draining as I drive", what leads you to that conclusion? Is the voltmeter in the instrument cluster EVER indicating less than approximately 12 volts?

First troubleshooting steps:

1. Approximately what voltage is being indicated by the voltmeter in the instrument cluster, under the following conditions:

1. Idle, no electrical load;
2. 2,500RPM, no electrical load;
3. Idle, moderate electrical load (headlights on, HVAC blower on high, rear defroster on, brake pedal depressed, AC on);
4. 1,200 RPM, same electrical load as #3 .

Knowing the system voltage under these conditions will help in determining what's going on.
 
#9 ·
its an 07 with 89K on the odo, original battery. normally the voltmeter is at the 3/4 mark around 16V.

yesterday when this happened it dropped to the half way mark and when I turned on the head lights I could see the needle drop. turned them off and drove home with running lights and watch the needle drop slowly on the way home. so there obviously is not juice getting to the battery from the alternator. I have drill this weekend so on sunday I will try and check output voltage from the alternator. What is the best way to do that? in the past on GM models I would pull the harness connector off and test on the alternator terminal.

replaced the alternator if that fixes shouldn't be a problem, but with the speedometer, turn signals, and accessories not working along with the airbag light, that what is confusing the heck out of me.

thanks again in advance
 
#10 ·
Todays alternators its not a good thing to pull the plugs to check output. U can check voltage output from the large 10ga wire.... its called the chargeback wire but also doubles as the voltage sensing wire for the internal regulator. Without the vehicle running you can check for 12v at the plug... this is the ignition wire to tell the regulator to send the signal to the field circuit to charge. The field circuit is internal to the alternator/regulator. Under no circumstances ever disconnect the battery cables to check alternator output as this is a good way to fry the alternator. Older cars ie early 80s and below were not effected by doing this. As far as your lights and such.... this is so common with denso and mittsu alternators when there is poor, no, or incorrect output... As a shop owner I used to see this weekly.
Normal voltage output for most vehicles is 13.8 to 14.2 with lead acid battery designs. 14.6 to 15.2 for true maintenance free batteries or high charge rate systems. The charging voltage can be checked directly at the battery. I check at the posts and at the terminals... the reading should be the same and if not it indicates a corrosion barrier even though you may not see it growing on the outside. This is the hard black crap that needs scraped off. The reason why you never disconnect the cables anymore is due to the filtering effect the battery has on the charging/electrical system. This is designed in as engineering. A bad charge back wire can cause the alternator to spike over 35VDC and feed this back into the vehicles electrical system. If I had a mechanic disconnect the battery as a test... I would fire them on the spot. I'm not buying an ECM, PCM, instrument cluster, radio, multiplex modules, ect out of stupidity.
If you have a DVOM multimeter, call me and I will walk you through testing your charging system. I will PM my number.
 
#11 ·
One more thing.... Why are certain lights, instrument cluster, and airbag circuit effected? It has to do with the 12V Ignition Circuit input to the alternator. AC bleed over on this circuit has strange effects on anything that is ultimately connected on this circuit as well. Usually this is a whole host of different things usually tied in at the fuse panels on the buss bar. So why does it effect newer cars more... its called a component within the modules called an AL/DL Converter which was not used in old vehicles... Basically it converters Analog Signals to Digital and the import cars incorporated this design along time ago. I've seen also cruise control and anti-brake systems wig out as well. It just depends on what all is on the same circuits and the sensitivity of the modules.
 
#12 ·
ALCON

I learned a valuable lesson...I thought I had checked every fuse but I did not. the 15A IG1 fuse was blown.

I believe from the previous owners installed wiring for an aftermarket subwoofer that the dealer cut the wire and cause a short.

I don't know for sure so I will keep and eye out on it.

shout out and 2 thumbs up to apachewink! A+ team player. thank you
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top