I did some research on auto a/c conversion and I'd like to share my findings and correct some misconceptions:
1. the one part that you will definitely need is "room temp sensor" (aka thermistor, costs $25 at the dealer). there is only ONE such thermistor for the truck, located behind the driver side "knee" panel. the 2pin harness is right there, I checked on my sr5 Tundra. do not confuse it with a different type of thermistor that's for the evaporator. the later one is on all models.
if you try to hook auto climate controls into sr5 tundra w/o extra parts (room temp sensor) the a/c will keep showing LO temp setting and max blower. you won't be able to operate it.
2. the temp control is ALREADY separated even on SR5 model. there is no separate blower or damper for driver or pasenger side that is not on sr5.
it's is true that Ltd Tundra has one more damper built into the case. that damper is called "cool air bypass damper". that single damper is common for both driver and passenger side, and it's sole purpose is to direct somewhat colder air to upper vents during hot days. that happens ONLY in Auto mode. if you manualy set the blower speed and direction of air flow, that damper remains in a closed position. in auto mode however, you set the desired temp and that's what blowing from the lower registers, but on hot days the "bypass" damper opens up so the air blowing from the top registers will be a bit colder than whatever temp you set.
Great info..Thanks..You are right the blower keeps blowing on max without any feedback from the thermistor..and it shows LO for the temp setting..but I am also getting no control from the mode switch (being able to direct which vents will opearate) but possibly having the thermo in the circuit will correct that aslo, we will see. I am going to the dealer tomorrow and will update as soon as I get the thermo installed (if it is in stock)....This is exciting and a very reasonable mod if it all works out..
glad I can help. last time, when I started a thread asking for help on that subject, trying to get some of those toyota pdf files, I got flamed and mods closed my thread. I ended up subscribing to TIS and went through most of the info.
back to the subject, I suspect that the solar sensor circuit will need to be dealt with also in order to have the controls working (notice how that auto ac panel starts in "auto mode" when plugged into sr5 tundra). the worst case would be to spend $106 to buy the sensor. but maybe shorting the circuit or installing a voltage regulator ($3) to supply the circuit with less than 0.8Volts would do the trick.
Interesting to note: I just bought an 08 RAV4 Limited for the wife last week and her car has the auto controls I just went out and checked and it has the solar sensor up near the windshield on the drivers side. I wonder if the plug is already installed at the factory on the Tundra and possibly it is just waiting there for the sensor?
glad I can help. last time, when I started a thread asking for help on that subject, trying to get some of those toyota pdf files, I got flamed and mods closed my thread. I ended up subscribing to TIS and went through most of the info.
back to the subject, I suspect that the solar sensor circuit will need to be dealt with also in order to have the controls working (notice how that auto ac panel starts in "auto mode" when plugged into sr5 tundra). the worst case would be to spend $106 to buy the sensor. but maybe shorting the circuit or installing a voltage regulator ($3) to supply the circuit with less than 0.8Volts would do the trick.
My auto control does not start in auto ..I'm still thinking I have a defective control. but I still I will need the solar sensor and thermo....How far did you get as far as your install? Did you ever get the part #s for the thermo and sensor? I am off to the dealer this morning maybe they will look it up...
My auto control does not start in auto ..I'm still thinking I have a defective control. but I still I will need the solar sensor and thermo....How far did you get as far as your install? Did you ever get the part #s for the thermo and sensor? I am off to the dealer this morning maybe they will look it up...
just because it doesn't start in auto mode it doesn't mean it's defective. I thought all of them start in auto because mine does, but now when I think about it, it may start in the mode it was used last .
it's definitely missing signal from the sensor therefore is inoperable.
the part# for "room temp sensor" (thermistor) is 88625-47021. conicelli has it for like $20, dealer sligtly more. the 2pin harness is right there.
we are working now on a big commercial site (construction) and are slammed with work, so I don't have any time off for truck projects. I can't wait to start working on that conversion, but for now I have to make as much money as I can, before it slows down again.
just because it doesn't start in auto mode it doesn't mean it's defective. I thought all of them start in auto because mine does, but now when I think about it, it may start in the mode it was used last .
it's definitely missing signal from the sensor therefore is inoperable.
the part# for "room temp sensor" (thermistor) is 88625-47021. conicelli has it for like $20, dealer sligtly more. the 2pin harness is right there.
we are working now on a big commercial site (construction) and are slammed with work, so I don't have any time off for truck projects. I can't wait to start working on that conversion, but for now I have to make as much money as I can, before it slows down again.
I was in construction before electronics as a union electrician for 26 years so I know what it's like when a big job is happening you have to go for it...I am on the Conicelli site and see the thermo but cannot find the solar sensor anywhere..Hope it is available seperately..Thanks again..I will keep everyone to date with my progress...
I was in construction before electronics as a union electrician for 26 years so I know what it's like when a big job is happening you have to go for it...I am on the Conicelli site and see the thermo but cannot find the solar sensor anywhere..Hope it is available seperately..Thanks again..I will keep everyone to date with my progress...
You might also get auto headlights with the solar sensor -- maybe just need to upgrade your headlight switch?. . .
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Wonder if we could tie a LUX sensor to a Voltage Regulator and feed the control or even a relay to the light circuit then a Voltage Regulator to give you a day/night mode.
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Pete
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Thermistor will be in tomorrow $23.16 not bad if it works..I am waiting to try that first before spending the cash on the solar sensor(opto cell circuit) $136.00 ...If the thermo does not do the trick I am going to try to shunt the solar sensor and see if that will null it out...Will give another update tomorrow..
Last edited by zekeman; 05-30-2008 at 03:55 PM.
Reason: wrong info
If I am not mistake there are two solar sensors, one on the drivers side and one of the passenger side.
As I read the tech manual, either of these is considered functional when they are applying 0.8 to 4.3 V, while light is shining on them.
Please check the PDF I posted above (Terminals of ECU, page #2) for the pin out for both of these sensors.
For $136 Each I’d make them myself given we know the specs and Radio Shack is right around the corner.
Frank
It seems as though there would be two sensors but I went to the dealer today and looked at a Limited and there is only one opto/thermo sensor on the drivers side and on my truck (SR5) there is a plastic cap covering up where the sensor would be....This is interesting, I do see on the ECU pinout where it shows a driver and passenger sensor and associated pin #s at J19-32 and J19-33 one for each for each and each has a GND return at J19-14..My guess is that the single sensor is actually a dual opto device remember it is not controlling the actual temperature of each side of the cabin.
there is only ONE solar sensor in the ltd Tundra, located on the driver's side, at the windshield. there is no solar sensor (aka light sensor) on the pass side. perhabs there may be one in the sequoia. the toyota documents are common for both models in that regard.
the sole function of the solar sensor is to info the climate control that there is a sunny day ---> that means that the solar rays warm up the skin and the uper body will feel somewhat hotter that the rest of the body ---> therefore the [earlier mentioned] "air bypass damper" will open up and the air blowing from the upper vents will be a little bit colder than the set temp. all of that happens only in auto function mode! if you manualy set the temp and blower, the solar sensor feedback is DISREGARDED.
the solar sensor provides the a/c amp module with the output voltage of 0.8 to 4.8 Volts depending on how sunny it is. anything below 0.8 volt is considered by a/c amp module as dark/no sun condition.
my earlier post is pretty much self explanatory. If anybody still thinks they have two solar sensors in their tundra, I'd be happy to take it off your hands (free), once you realize you need only one
BTW I hate to go off topic, but anybody cares to explain the "day/night mode"? also, does ltd tundra have auto headlights? does that mean they adjust the hight automaticaly or they turn on automaticaly? thanks
....This is interesting, I do see on the ECU pinout where it shows a driver and passenger sensor and associated pin #s at J19-32 and J19-33 one for each for each and each has a GND return at J19-14..My guess is that the single sensor is actually a dual opto device remember it is not controlling the actual temperature of each side of the cabin.
Bingo! Give Zekeman the cigar (or beer)!
There are two Solar Sensors in a dual optical device, right and left side in one physical device.
There is a 6-pin connector on the solar sensor, pin #1 is for the Drivers side (TSL), Pin# 2 is the Passenger side (TSR). These are outputs. 0.8 to 4.3 V A/C Amplifier.
Pin #3 is Ground and Pin # 6 is +V.
Attached is a PDF on how to test the Solar Sensor.
I am on the Conicelli site and see the thermo but cannot find the solar sensor anywhere..Hope it is available seperately..Thanks again..I will keep everyone to date with my progress...
I posted part# for room temp sensor earlier.
if you're looking for solar sensor on conicelli or sparks site go to:
Re: Change Manual a/c heater to Auto digital
Linear Mode
