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Low beams randomly don't turn on, left or right, never both
Hello lovely people. Recently bought my 2007 RX350 with 149k on the clock. It's been doing this very frustrating thing lately.
At random times, one of the low beams won't come on. Sometimes the left, and times the right. Turning the car completely off, and then turning back on works, sometimes. And sometimes it doesn't. Where do I begin? It's either one of them that'll definitely come on, or both. Never have I had the instance where both wouldn't come on.
As I type this, powered up the car, no issues. Drove home. Parked up, shut down, restared, the right bulb didn't turn on. Manually turned them off, and back on, and now both are working. WHY IS THIS HAPPENING???
The headlight circuit is complex and the left and right headlights have dedicated fuses and a dedicated solid state relay for each side that powers these fuses.
However, both relays are activated by a common control signal(red wire, 0V) from the Body ECU.
When it hapens, plz check for voltage at the fuse on the headlight that's dead, this can hopefully help us narrow it down.
H-LP R Relay --> powers on "Right Low Beam Headlight Fuse" labeled H-LP R- check this fuse for voltage if right low beam is dead
H-LP L Relay --> powers on "Left Low Beam Headlight Fuse" labeled H-LP L- check this fuse for voltage if left low beam is dead.
*Note- these solid state relays are located on a circuit board inside the engine room junction/fuse box but hopefully don't need to go there.
It is highly unlikely that you have a bad fuse. It is very rare for a fuse to work, then not work, then work again.
Checking the voltage when a headlight is not lit up is a good start. If the non-illuminated headlight has voltage, start wiggling things at that headlight.
Wondering if you have the HID low beams. If so, is it possible that the HID igniter/ballasts (not sure of the actual name) Or HID bulbs are reaching the end of their life and need to be replaced?
Wondering if you have the HID low beams. If so, is it possible that the HID igniter/ballasts (not sure of the actual name) Or HID bulbs are reaching the end of their life and need to be replaced?
It is possible but would like to do everything possible BEFORE I get round to purchasing new lights and ballasts.
yes. Happens with both auto and non auto. This morning, the right low beam came on. The left didn't. Turned the car off and on a few times, manually turned the lights on and off a few times as well, and then finally the both the lights came on together
So a bad fuse can possibly do this? And not just completely go out aka lights not coming on at all, period l?
Very unlikely a bad fuse happens, but testing at the fuse tells you if there is power in that circuit so you know if it is a wiring issue or not. If you find power at the fuses then next check for voltage at the headlight itself. Basic step by step diagnostics.
I had the same problem, sometimes the Left side would come on, sometimes the right side work come on, the only difference with mine is sometimes Both would work normally
it was the HID Headlight bulbs
As they age they will cause electrical issues and not perform normal
I replaced both bulbs several months ago and No more issues
So if you have HID Headlight bulbs I would recommend replacing them
switch on power.
right low beam head light switches on not instantly but takes up to two seconds to get into full power, from dim to full bright light.
then it switches off after 30 or 40 seconds.
but sometimes it works and sometimes it does not switch on at all.
during the ride if i switch off the lights and switch back on, right light is off... but if i wait for couple of minutes and try again it might switch on and work... or switch off after several seconds.
bulb was changed after only 7 months.
was burnt inside.
The same thing happened to me with my 2007 Lexus RX350 sometimes the left side wouldn't come on, but the right side would come on, I wound up removing a lot of parts to replace the hid bulb,a couple of months later the right side started to not come on
I told myself that I'm not removing a lot of things again, it was hard but I replaced the hid bulb without removing the front end like I did on the left side, it's just a spring clip that holds the bulb inside, helps if you have small hands, I have large hands but I managed to replace it,get a small inspection mirror to help you see
11-12-21, 07:37 PM
Low beams randomly don't turn on, left or right, never both
