[Lowbeambandit]

Driver side low beam doesn't work, however brights work. Changed bulbs already and no luck. Not sure what fuse or relay to check. Didn't see any noticeable corrosion in the bulb socket. Nothing coding. Anyone have any insight on this?

Thanks in advance

 

[VStar650CL]

The gen6 Altimas don't have fuses, they have P-MOSFET transistors in the IPDM (Nissan calls them "Smart FETs"). The FET's will quit working if a short or overload is detected, then reset when the problem is resolved. However, you only get 50 detections in a row and then the IPDM is permanently screwed. The first thing to do is put a test lamp across the bulb connector terminals with the bulb removed, if that lights then you have a connector problem. If it doesn't, check from the low beam wire to a chassis ground, if that lights then the ground wire is broken. If that doesn't light, then start tracing back toward the IPDM.

 

[PowerslavePA]

The count is wrong. The fifth attempt to operate the headlights advances the retry counter
by 1. Eventually, this counter could reach 20, which means the IPDM has recorded 100
retries (20 times 5). If the retry counter hits 20, it bumps the circuit malfunction reading from
0 to 1. Now the system permanently shuts off the power supply to the failing circuit; for
example, it’s the headlights. If this happens, there’s no way to reset the IPDM with a scan
tool or other procedure. Instead, you must repair the circuit and replace the IPDM.

This does not pertain to an open circuit! This counting condition only occurs on what would
normally blow a fuse. An open circuit would be a blown bulb as well. This will not set any
counter for a failed attempt, because there is no short that caused the Smart FET to turn off. SO, if the failed side is just because the circuit is open, it will not advance any counters.

For one thing, on the 5th attempt to use the headlamp, and there is a short, the smart FET
system sets a DTC for the shorted circuit and shuts off power to the headlight circuit.
What’s more, the power remains off until the person shuts off the ignition switch and turns
it back on again.

You get 5 attempts per key-on cycle, before it sets the retry counter by +1. If you turn the
car off, before the 5th try, it will not +1 the retry counter the next time you key on and turn
the headlamps on.. The attempts counter gets set to 0 when you turn the car off. So, the
chances of reaching 20, for 100 tries, would mean you would have to use all five attempts
at once, every key on cycle, 20 consecutive times. As said, only for a short.

Need both lo-beams? You would need to hook a relay up to the working headlamp, and
have the replay power the other bulb until you can get it fixed. I have done this before, and
it works. Splice power from the working bulb, to pin 85 of the relay (coil), then pin 86 (coil)
to ground. Battery Power to pin 30, then pin 87 to one of he bulb socket wires, then the
other lead to ground. You would need to buy a H11 socket with two wires so you can do it.
I had to do this with a buick, and it's still jumped like that to this day. He never got his
module fixed...

SO, when you turn the headlamps on, the relay latches, and powers the other bulb from a
separate power source. The jumped circuit is removable. Also, since you will not be
powering the headlamps on and off 5-times with they key on cycle, the retry counter will not
advance if there IS a short.

You can also use lower (55) watt as hi-beam bulbs, and run with the hi-beams on, and
unplug the other lo-beam bulb.

Anyway, here is an interior fuse diagram in case you need one:
2020 Nissan Altima fuse box diagram - StartMyCar - Interior Fuses.

 

[VStar650CL]

The count is wrong. The fifth attempt to operate the headlights advances the retry counter by 1. Eventually, this counter could reach 20, which means the IPDM has recorded 100 retries (20 times 5). If the retry counter hits 20, it bumps the circuit malfunction reading from 0 to 1. Now the system permanently shuts off the power supply to the failing circuit; for example, it’s the headlights. If this happens, there’s no way to reset the IPDM with a scan tool or other procedure. Instead, you must repair the circuit and replace the IPDM.

That's all correct, I misremembered the count. However, to avoid chasing one's tail, do put a test lamp on the headlight connector first. The vast majority of one-bulb-out issues turn out be poor pin or bulb connections or broken wires, usually right at the connector. Checking with an independent test bulb at the headlight connector tells you immediately what part of the circuit the problem is in, and you can chase it up or downstream from there as needed.

It would have been more helpful if Nissan had put LED indicators on the IPDM to show the condition of the SmartFET's, but I suppose it wasn't cost effective. Very few scanners will read the IPDM, so the DTC's it throws when the FET's are shorted are pretty much useless to the average DIYer.