need a/c help! solar sensor and pressure sensor - Toyota Nation Forum : Toyota Car and Truck Forums

breaze · 07-19-2011, 12:41 AM

okay first off, i am new to this forum but new to forums in general and i know how to use the search button on forums, i did and after and hour and a half and going through more than 100 pages of threads and posts i cannot find an answer.

the car is my wifes 1999 solara sle v6 auto trans and auto a/c.

the a/c started blowing HOT, almost as hot as the heater, i know its not the coil temp sensor cuz it is 115!!!! outside!!!!

the a/c is charges and has dye in it, there is no leaks.

i did the a/c dtc check and the codes came up with with 21 and 23.

solar sensor and pressure sensor. so i bypassed the pressure sensor and turned on the car and a/c. nothing changed, i then reset the a/c ecu by pulling out the ecu-b fuse while leaving the jumper wire in the pressure sensor. code 23 went away but 21 (solar sensor) is still there.

I have no idea where the solar sensor is, what it does and how to test it. please help me! i live in phx az and it gets to 120 here sometimes. and to add to it me and my wife just had a baby, so my wife and my 4 day old daughter NEED A/C!!!!

this would be easier if i was a toyota guy, I am a chrysler jeep dodge certed with honda knowlege from owning one.

so please help me.

71Corolla · 07-19-2011, 01:18 AM

I'm not sure exactly where it is on your car, but look for a button shaped thing near the vents/edge of the windshield. Also take a look here.

71Corolla · 07-19-2011, 01:49 AM

The part is refereed to as "THERMISTOR, COOLER (SOLAR SENSOR)" so that does sound like it does tie into the A/C system.

Stillrunning · 07-19-2011, 06:32 AM

Quote:

Originally Posted by breaze

i did the a/c dtc check and the codes came up with with 21 and 23. solar sensor and pressure sensor.

The SS will be located on top of the dash some where, probably round shape. If you have the headlight auto on/off there will probably be another sensor for that, but the same sensor could be used for both A/C and headlight control. Sensor will need to be removed to test it. I don't have values but essentially you'll need an OHM meter to test changes in resistance with more/less light. I'd test it covered up (no light) and with max light using an incandescent light to see if you get different OHM readings. I don't know if a bad sensor can completely prevent the compressor from engaging. I assume you have checked to see if the compressor is engaging or not. This is a climate control system, have you tried putting it in "Manual" rather than "Auto" to see if that makes any difference.

Quote:

the a/c is charges and has dye in it, there is no leaks.

Never assume system is charged. I'd pressure test it.

dc_98_cam · 07-19-2011, 09:43 AM

The wiring diagram for the pressure switch shows 4 contacts.
Two wires are for the magnetic clutch. The other two are for the condenser fan. ....Maybe you have to jumper both pairs to get it to work.

I would just check for clean electrical contacts on the solar sensor .... also check for some reasonable value of resistance .... not open .... not shorted.

hill8570 · 07-19-2011, 11:10 AM

Hard time believing a solar sensor failure would cause the A/C to not cool -- that's not a reasonable fail-safe.

Do you have a gauge set? Behavior of the high/low system pressures would be useful.

BTW, just because it's 115 out doesn't mean you can rule out the expansion valve (I assume that's what you mean by the "coil temp sensor"). Toyota expansion valves are crap, and often fail "full open", which makes for really lousy cooling. Usually pretty easy to diagnose -- your low-side pressure will be a bit too high, and high-side pressure a bit too low...basically means that the refrigerant is moving through the valve faster than the compressor can keep up.

breaze · 07-19-2011, 05:18 PM

thank you all for your input, i am going to check everything you all mentioned.
im also going to use my u/v light and check for leaks under the dash.

i will get back to you all when i find out the culprit.

LEEcoqui · 08-11-2011, 09:22 PM

I also have the same problem on my 1999 SLE V6 Solara.

After running the diagnostic (holding down the AUTO button and the inside/outside Air circulation button at the same time while turning the ignition to on) I got back the code 21 - Solar Sensor.

In my case the A/C is working perfectly. However, it is stuck in 75 degrees temperatur. It will not change temperature even if I want to turn the heater on or to a colder setting. I tried manual or auto. Either way the dial does not respond to any change in temperature.

Does anyone have any more info on how to replace this Solar Sensor and if possible a part number?

Thank you.

***fenixus*** · 08-11-2011, 09:42 PM

Toyota OEM Solar Sensor 88625-33150, ~$27 online + s/h, e.g. from here:
http://www.toyotapartszone.com/oem/t...625-33150.html

or contact our member vendor TOYOPARTSMAN (Gary) from Newnan, GA, he might give you a better price (more discounted) and lower shipping charge on something small.

to replace it, you just gently pry it out with a flat screw driver (cover it with masking tape to avoid scratches), it should pop out, then disconnect the plug, replace and re-install in reverse order

reidcc · 08-12-2011, 03:59 PM

To the OP-

The Solar Sensor is on the left top side of dash(with a dome over it). It does NOT come out easy. There is not much room, and the two clips holding it in are directly in the front, and directly in the back. I worked getting two out of wreckers to try in my situation.

Before you go through that trouble- make sure you are in the sun and the sensor is in the sun, and THEN run the test. U may find it works fine.

To the Guy who only gets 75 degrees- Leecoqui-
What exactly do you mean by stays at 75- when you turn the knob it will only read 75, or are you saying your temperature always stays the same regardless of what the LCD says?

I can't believe I am only seeing this thread now- as I've had a similar thread about no mixing on my Blend door. I've replaced the 3 sensors, and the LCD control panel- all with ZERO change.

Chris

ghettosled · 08-12-2011, 08:54 PM

check the pressure on the low side and see what you are holding at. should be about 40-50 PSi if i recall. anything below about 5 PSI will be too low to kick on the clutch and compressor. when you turn on the AC, i take it the compressor doesnt even turn on?

common leak points seem to be the o-rings at the front of the condenser. i read the o-rings by the expansion valve and the expansion valve are also other weak points in the camry's AC system.

LEEcoqui · 08-13-2011, 03:22 PM

The temperature luckly stays at 75, the display stays at 75 and absolutely nothing change from 75 when I turn the knob. Turn the A/c off and when back on = 75 degrees. Remove the battery from the car, back on, start the car - and it it back to 75 degrees. One good thing it is providing nice 75 deg cool air in the middle of this torching summer.
I hope replacing the solar sensor will fix it. According to the test : code 21 (solar sensor) is the veredit!
I already pulled off the sensor quite easy. Did not have any trouble pulling it out. It is back on until I get my hands on the new one.

LEE

Quote:

Originally Posted by reidcc

To the OP-

To the Guy who only gets 75 degrees- Leecoqui-
What exactly do you mean by stays at 75- when you turn the knob it will only read 75, or are you saying your temperature always stays the same regardless of what the LCD says?

I can't believe I am only seeing this thread now- as I've had a similar thread about no mixing on my Blend door. I've replaced the 3 sensors, and the LCD control panel- all with ZERO change.

Chris

***fenixus*** · 08-13-2011, 07:04 PM

good luck with new solar sensor, I hope it fixes your car

reidcc · 08-15-2011, 08:15 AM

Yah- good luck on the sensor... its a cheap replace.

I can't answer about the LCD panel not changing, although maybe the knob shaft is much like a "volume control" and needs cleaning. There are prodcuts like Faderlube to clean carbon out of the shaft and "pot" inside- but I don't know if ours are like that. The other alternative is to replace the LCD panel from a junker or from the 'bay. I paid $30 for mine.

Chris

LEEcoqui · 04-26-2012, 10:26 PM

Quote:

Originally Posted by LEEcoqui

The temperature luckly stays at 75, the display stays at 75 and absolutely nothing change from 75 when I turn the knob. Turn the A/c off and when back on = 75 degrees. Remove the battery from the car, back on, start the car - and it it back to 75 degrees. One good thing it is providing nice 75 deg cool air in the middle of this torching summer.
I hope replacing the solar sensor will fix it. According to the test : code 21 (solar sensor) is the veredit!
I already pulled off the sensor quite easy. Did not have any trouble pulling it out. It is back on until I get my hands on the new one.

LEE

Update: After replacing the Solar Sensor the A/C is still stuck on 75 degrees. It will not change temperature when turning the temperature knob.
Back to the same. The code 21 - Solar Sensor was not the problem. Bummer.