I have a 2015 IS350 non F-Sport with the fog lights. They came with the LED fogs which I switched out for the halogen fogs to put yellow 2500k bulbs in (I prefer them to the LED). I switched them out probably 6 months ago, and last week I noticed both bulbs were out. I assumed it was just the bulbs, so I changed them out for new ones yesterday. I plugged the bulbs in and they came on fine for about 3 seconds and then shut off. I turned the switch on the stalk off and on, and again they came on fine for about 3 seconds then shut off. They are continuing to do this.

Has anyone experienced this before? Could it be an issue with the wiring not being able to support the 55w halogen bulbs since they were wired for the LED? I don't see why that would matter but I don't fully understand wiring and wattages so who knows. But if that were the case then why would the first set of bulbs last 6 months?

I changed the bulbs on my 2008 IS-F as well and never had an issue.

Any help / input is appreciated.

 

Here is the path of the Fog light signal:
- Stalk switch is turned ON, and sends a signal to the Main Body ECU
- Main Body ECU sends a signal to the Semiconductor Power Integration ECU (which is in a junction block under the hood)
- Semiconductor Power Integration ECU sends power to the Fog lights
- The Fog lights are always grounded, so they just need power sent to them to turn them on.

If the Fogs are only coming on for a few seconds and going out, then likely the Semiconductor Power Integration ECU is shutting off the power supply for whatever reason.
Why the first set of bulbs lasted 6 months? Maybe the specs for those bulbs are not exactly the same as the replacement ones you now have.

 

Thanks for the response.

The first bulbs were also 55w so I have no idea why they lasted that long.

 

I should have been more specific, is it the same brand and model of bulb as the first set?
Even though they are all 55W's, from manufacturer to manufacturer there will be some variance...like buying a 225/40/18 tire Bridgestone, and one from Michelin...the numbers say they are the same, but physically they are not.

Also, if you still have the original LED bulbs, put them back in and see what happens.
If everything works fine, then it's just your halogen bulbs, if it's still happening, then it's likely something else...like the Semiconductor Power Integration ECU.

 

I sold the LED ones, or else I would have put them in to see what happened. I did not expect this to be an issue. A lot of guys with IS-F's with the halogen fogs put the LED ones in with no issue so I assume the wiring is the same. Maybe it's different when you go from LED to halogen.

 

 

That's pretty much my conclusion as well.
Going from Halogen to LED is not an issue as the LED uses less power.

My suggestion would be to figure out what the LED bulb was rated for, and get the Halogen equivalent in wattage.
You had put a 55W bulb in, but how did you arrive at 55W as the correct replacement? Or did you just want a 55W bulb in the fogs? If I had to guess, I would say that 55W's sounds like the bulb is would have come with if it didn't have the LED bulbs.
A 55W halogen bulb would be about a 13W LED bulb.

The puzzling thing is the Semiconductor ECU appears to be the same part regardless if the Fogs are LED or Halogen.
I'm assuming the ECU is acting as the Fog relay in the circuit, so it shouldn't matter what bulb is in there in terms of LED or Halogen.
My only guess would be if the halogen bulbs are rated at 55W, but in reality draw much more wattage, and therefore the circuit is shutting down due to overload or heat.

 

The stock halogen bulbs on the 2is are 55w, I put these same bulbs in my 08 IS-F and never had an issue.

Overloading the circuit would make sense, but what doesn't make sense is the fact the first pair of 55w halogens I put in lasted 6 months.

If it's the circuit can I change it to handle the halogen?

 

Not at this point...everything controlling the Fogs are going through a computer of some kind.
The only option would be to create your on Fog circuit in between the switch and light, therefore bypassing the computers.

Just wondering if anything had changed with the vehicle prior to the first set going.
I mean to say, was there anything installed on the vehicle of the electrical nature...like an alarm, remote start, dashcam, etc....anything at all.
Why I ask is the Semiconductor ECU controls other things than the Fogs. So if other electrical devices were added, it may be effecting the overall performance of the ECU.
The ECU is fused with an 80A fuse, so clearly it's using a fair bit of power to operate stuff.