Alt fuse 2004 4runner

was not on before the new alt,? is alt new or used.?
or came on only after the new ALT?????????
my guess, is 2 failures.! (one ignored and 2nd grew)
on with engine running, guess yes.
Good question and is same answer on all cars.
1: engine rpm too low, what is yours (below 80 rpm)
2: fan belt slips. bad tension pulley (weak and old???)
3: Alt bad, or its wires bad.
4: brake level low, (@MC) or hand brake switch stuck on, or other brake failures. a plenty, scan the PCM and ABS if you have ABS.
id not drive it with the brake lamp on (Savvy?)
the battery light is really the ALT charge lamp.
it glows anytime the Charge system can not charge the battery
if you drive far like that, the engine will stall and not crank.

5: the horn fuse power the alternator, so check the horn fuse
10amp , key on, 12vdc on both sides of fuse is needed/
fyi: the meter fuse runs the charge lamp, if said lamp is dead bingo.
6: fact 2, the PCM does NOT run the Alternator on the 3.2L .
7: alternator case not grounded right.
8: battery is bad, causing alternator to drop off line
9: battery cables bad, at the 4ends or they are bad.
10: the plug on the rear of alt is bad or its wires or pins rusty.


brakes:
the brake lamp has 3 inputs ("OR" logic) master cylinder level low.
the hand brake lever and the EBCM (electronic brake control module)
a technician unplugs each to see what causes the error.
if you unplug mC wire and hand brake wire
then the EBCM is UNHAPPY, scan it.

ckeck main fuses, also alt has a fuse ! check connections
between batt and alt.

Your alternator-mounted voltage regulator has failed. Luckily, your voltage regulator is
replaceable separately from the alternator (most voltage regulators are integral to the alternator,
and cannot be separately serviced).

Note: this works for 3.8L cobra alternators/voltage regulators only - in the 4.6L model, the
voltage regulator is an integral component of the alternator.

1999 Ford Mustang Cobra -3.8L engine

3.8L Engines

1. Disconnect the negative battery cable.

2. Remove 4 Torx® head screws holding the voltage regulator to the alternator rear housing. Remove the regulator, with the brush and terminal holder attached.

Fig. 1. The regulator and brush/terminal holder are mounted on the backside of the alternator




Fig. 2. The regulator and brush/terminal holder are secured by 4 Torx® head machine screws




Fig. 3. Hold the regulator while removing the screws to prevent the regulator from dropping out and damaging the brushes





3. Hold the regulator in one hand and pry off the cap covering the A terminal screw head with a small prybar.

4. Remove 2 Torx® head screws retaining the regulator to the brush holder. Separate the regulator from the brush holder.



Fig. 4. Slide the regulator out-the brushes will move out of the holder




Fig. 5. The brush and terminal holder can be separated from the regulator once it is removed from the alternator




=========================================================
To install:

1. Install the brush holder on the regulator with 2 retaining screws. Tighten the screws to 25-35 inch lbs. (2.8-4.0 Nm).

2. Install the cap on the head of the A terminal screw.

3. Depress the brushes into the holder and hold the brushes in position by inserting a standard size paper clip, or equivalent tool, through both the location hole in the regulator and through the holes in the brushes.

Fig. 6. When installing the regulator, press the brushes back into the housing




Fig. 7. Use a thin piece of soft material, like this plastic wire tie, to hold the brushes in position while replacing the regulator, or use a paper clip inserted in the hole





4. Install the regulator/brush holder assembly and remove the paper clip. Install the attaching screws and tighten to 20-30 inch lbs. (2.3-3.4 Nm).

5. Connect the negative battery cable.

Sounds like fusible link. It's a thick (thicker than normal) wire coming from battery to junction block on firewall. They burn through and/or break down internally - you can replace it with an inline 30amp fuse & holder.

Hello and Welcome to FixYa!
Check for the fuses and relays, located in the Engine/ Driving Compartment.. The fuse/relay for the Headlights will be marked on the casing of the fuse holder. You have to locate that fuse and have to replace it in case of bad/ faulty. Also do make sure, that the Switch that performs the High/Low beam operation is properly working. Worst case scenario would be the bad filament/ projection tube usually called bulb/ beam.

Concerned.

hi simon
this definatley sounds like you have a short in the system basicly, whats happening is, when power is transmited to what ever the fuse is attached to is shorts out ( an earth touching live, or vise versa ) what you will need to do is find out what the fuse is for, when you have that this should be then a simple case of locating the item involved and checking wether it is or part of it is touching a positive or negative where it shouldnt be, sometimes a clisic case is , a bulb has been changed and when the replacment has been put back in the holder, the contact for the holder can sometimes get bent and touch the opposit polarity hence this causes a short circut ( it happend to me and took me a while to sus it out myself lol ) i hope this sorta helps

Hi , remove the brake light bulb and look at where the bulb contacts the holder , you may find that you have a hole burned into the holder where the contacts have been arking , if this is the case you will need a replacement kight unit , reagards mark

Replace the blower control module. Its under hood about six inches from the ac/heater fan motor on heater case hidden behind a shield. It bolts in from the top and has about eight wires going to it.

check and see if you have pinched the wires when placing the tranmistion to engine.

Alternator ? Is your alternator charging? What type of electrical problems are you having.