I know I was shocked when Bgw70 started talking about A/C. I have yet to deep dive into that quagmire yet. But I truely thought that photo sensor was strictly for the lights automatic function. I have learned more than I expected which for me always raises twice as many questions.🤔 Lol.

Paul

 

I know exactly where that is. I will clean it and let the forum know if that works.

 

Are we talking about the sensor in front of the passenger seat up on the dash. If so, I just went out and put the lights on AUTO. Being in the sun, of course no lights came on. I then covered the sensor on the dash and about 15 seconds later the lights come on. That sensor is for the AUTO light function not the AC heating system.

 

The only thing confusing the situation I believe is the terminology "Solar Sensor". I identified that the sensor itself as an "Automatic Light Control Sensor" connected to the Drivers Side J/B ECU. After reading Cinc04 post above I did dig a little deeper. The sensor transmits and receives a data stream and that information is available to other systems, such as the A/C Control Assembly". I have not had a chance to completely understand everything going on the in the various ECU's. I could spend weeks doing that alone. I learn something new everyday. Kudos again to Cinc04 for his thorough write up. Everyone remember to give him a like.😁

Paul

 

Thank you Raven01750 for your comments. I believe your technical comments are absolutely correct. My terminology was confusing and I apologize. I certainly didn't intend to confuse the issue.

My manual shows the location of the device and it does call that an “Automatic Light Control Sensor”. In looking at my manual for the vehicle electrical wiring diagram, it shows the location of the wiring and it goes directly to that sensor on the dash. In the legend, it shows that as location A26 and is labeled, "Automatic Light Control Sensor and AC Solar Sensor".

Just as Raven01750 mentions, my understanding is that the sensor does a couple of things, it does provide a sensory function for the headlight auto-control function and it also provides a sensory function for the AC system.

I too went into that rabbit hole that Raven01750 mentioned. I hope that DAVEB1980 comes back and says he cleaned the temperature sensor and now his AC system works perfectly.

 

Im going to pop the sensor out and clean it tonight!

 

​​​​​​​😂😂😂 the auto beam when I go in tunnels or park in my garage.

 

Well popping out the sensor and cleaning fixed it fixed issue. My AC blows cold now.

thanks for everyone's help!!!

 

WOW. I'm shocked. Details please. How did you remove the sensor? What was dirty? The lens or ? Glad it worked for you. 😁

Paul

 

I went under the dash and popped the sensor out. It was totally dirty by the connectors and needed to be cleaned.

 

Which one? There are two of them.

 

All I can tell you is the sensor up on the dash is the "headlight control sensor" Page 97 of my 06 manual. I confirmed this with a call to the Lexus dealer in Greensboro NC. It has nothing to do with the AC.

 

Bgw70 should get a cold beer for this.

 

BGW70 did a great job with the diagnosis.

IOLMaster made a comment on the sensor issue that first started this thread. I have been wrong before, but here is what I was basing my information on:

Here is a page from my electrical wiring manual, 2004 Lexus SC430. This shows the position of parts in the instrument panel. Under A26, they show "Automatic Light Control Sensor and A/C Solar Sensor". This point to one location, on the upper right side of the dash. It shows one connection and it appears that there is one device that provides light control and provides an in[ut for the A/C system. The actual wiring diagram shows the A/C Solar Sensor is connected to the A/C Control Assembly at connections TSDr and TSPa.

 

I forgot to put in the electrical wiring diagram. The A/C solar sensor is at the bottom middle. It is connected directly to the A/C Control Assembly. Note they show this as A26, the same as in the diagram for the dash layout.