Any kind soul able to help where can I install this diode fuse if my toyota fuse box doesn't have ALT S 7.5A fuse? the only 7.5A are for AM2 in my toyota. Running on Din alternator socket 1 cable alternator. Looked high and low for answer but can't get any stuff to boost my charging above 13.8v

What year is your 4runner? I thought all had the alt s fuse.

Did you figure it out ???
Im trying to help a buddy with a 2020 4runner.

I encountered the same issue with a battery light coming on

You do have one ... its on the middle row closer to the driver side fender part of your fuse box. In between the 10amp and 15amp fuse.

But the GM Diode fuse mod doesnt work because you have to deal with a battery light on the dash

From Arclight website:

VOLTAGE BOOSTERS ARE NOT COMPATIBLE WITH 2020+ 4RUNNERS DUE TO CHANGE IN FUSE BOX LAYOUT

yup I saw that.

I was using the GM Diode Fuse mod. I wonder if the other fuse mod works ...

anyone found a go around???

For the Arclight VB, has anyone leave it in "overboos"? I've been testing mine in overboost mode. At initial start, my voltage will go 14.9-15.0V for a few minutes, but once it's running steady, it settles at 14.4-14.6V.

I have an odyssey 34r, and the optimum charge voltage stated is 14.4 - 14.8V. But my question is, for the first few minutes when I start my 4runner, and the voltage goes to 15V for a few minutes, would that damage my AGM in the long run?

I feel that leaving the arclight at just the "boost" mode, the voltage is not enough to charge the AGM. It will be in the 13.7-14.2V range.

Any feedback is greatly appreciated. Thanks in advance.

nope it's doesn't work on my car since totally there is no alt s slot at all. tried replacing all my 7.5A fuse but no reaction totally to charge high and remain same 13.5-13.8 still. any soul able to do Magic to newer model 1 cable toyota denso alternator to let it charge high?

Hi Chilow,

BY ALL MEANS; leave the VB in-line! It'll help compensate for the high resistance in the Jumper-cables, and the small clamp connector surface-area!

~rig~ Cheers!

Hi Gill925,

The "Tell-tale lamp" circuit works this way... In the D/S (fuse) Junction-box, there's a 7.5 Gauge fuse HOT in on or Start!. It's directed through a diode, and an LED (Instrument Cluster//Tell-tale lamp circuit)! It goes to the Alternator L terminal #4 (Pink wire).

If the L Term at the alternator is generating voltage, then there's "NO GND" for the battery lamp to work, so it stays off. If there's NO Power/Voltage at the alternator's L Term, then the HOT Gauge fuse finds a GND at the L Terminal, and so it... lights-up to let you know the alternator isn't charging!

I would check that 7.5A Gauge fuse FIRST, before condemning the alternator! Also the IG Terminal #2 on the alternator, a 7.5A IG1 (IGN fuse); also in the D/S fuse-box, supplies power to the alternator's rotor, so be sure to check that fuse; W/O that power source, "NO CHARGING!"

Please let us know how you made out... although I see this is an OLD thread; but someone may STILL be able to benefit from these talent guys here who are helping out phenomenally; which is just why this is the LARGEST 4Runner forum in the U.S.A!

~rig~ Cheers!

Hi BlueMica,

If you have a 5'th Gen 4Runner, then here's where to look: At the TOP of the "Engine-room fuse-box", you have the: SHORT-PIN, below that is the 10A RAD#1 fuse, below that is the, AM2 7.5A! Right next to that (to the Right), is the 20A H-LP HI (High-Beam fuse). And right below that is the: ALT-S 7.5A Alternator (S) (Sensor) fuse that you're looking for!

Hope this helps!! ~rig~