BobQ

I get a DTC 21 which is the solar sensor. RX300 2003 and 120kmiles.
Tech service bulletin TSB2072 has info for testing various sensors but lacks info for how to get the dang thing out. Sitting in the driver’s seat it is just to the right of the light sensor (dims the instrument lights at night).
I can get the lid (cover) off the top but then I have no idea how the rest comes out. I hope it lifts upward vice going down into the vast maze behind the dash. What is the procedure?
Also the
If the solar sensor is bad, what kind of symptoms should I have?
Bulletin TSB2072 lists four variations of the solar sensor based on if the car 1: [is equipped with automatic light control system] and/or 2: [AC with Left/Right independent temp control] To my knowledge the RX300 does not have a Left/Right independent temp control but I think it does have an automatic light control system.
Given the Solar Sensor will show infinite resistance at night and some conductivity in sunlight. Shouldn’t the AC continue to blow cold either way?

salimshah

Be careful with the solar sensor error message. Everything can be OK.

Some one please confirm or correct me:
If the self test is conducted in a garage (covered area), you will get a fail.

Salim

BobQ

thanks, I was outside, direct sun on sensor. BUT I'm not going to a lot of effort regarding this sensor since my AC is working but not on the passenger side.

BobQ

ALSO: My main question is how does the solar sensor come out?

carguy07

Looks like it just pries out.

derreckla

what were the results?

My ac stopped working on the passenger side rear as well

Thanks

salimshah

I am missing something here ... What is the connection between the solar sensor and ac for the passenger side + rear?

I think your problem might be with the servo.

Salim

GHBabie

I think they're peeking down the road of possibly having dual climate control, since that's mentioned in the OP as a differentiating factor between variations of solar sensor, per that TSB.
I would think it would be more apparent based on actual buttons if DCC were present (every vehicle I've been in has had separate controls for driver and passenger, and a button to flip between dual and mono(per se?) and that it probably is the servo, a whole separate issue with no bearing on the solar sensor.

GHBabie

Don't let all this confuse you; this is a weird spam account.

Good catch [post deleted and sender notified. Cut and paste are not forgiving ... Thank You. Salim

Xai

I can’t seem to find the bulletin you mentioned. Can you drop the other two symptoms of a bad solar sensor?

salimshah

Before anyone gets too far, please keep in mind the result can be false if the check is done in the garage. Make sure the vehicle is out in the Sun.

Salim

Xai

I’m having A/c issues. The compressor doesn’t kick on. I’ve swapped out the climate control, magnetic clutch relay, vacuum checked and filled system at a local shop. I don’t believe there’s a break in wiring anywhere as the compressor turns on and blows cold air when I jump the relay at pins 3 & 5. I’ve also jumped the pressure switch in the front of the car and nothing happens. A/C light is on on the climate control and car has never been in an accident as to possibly having severed wires.

Planning on swapping out the solar sensor. I believe it’s the one that’s connected to the vent believe the windshield. If anyone has any other similar issues please feel free to share.

Update: The DTC 21 Solar sensor disappears if dine out in the sun so back at square one.

Xai

Yes, if conducted in the garage DTC 21 for solar sensor will appear but won’t if done out in the sun.