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Old 05-29-2008, 09:34 PM
zekeman zekeman is offline
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Default Re: Change Manual a/c heater to Auto digital

Quote:
Originally Posted by PENER View Post
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..
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