UncleRico

iTrader: (6)

Ive had the truck for about a year now and always using either the heat or ac pretty regularly with no issues. The first time I noticed something was a little off I had the heater on but it was blowing ice cold air out of the vents(yes engine temp was high enough for heater to work). I had the heat turned up to the highest position with the ac button tuned off and it didn't matter what the fan speed was on or if it was on outside/recirculate. Then just the other day it was a little warmer out and I turned the AC on and then it started blowing out hot air. At first I thought obviously the ac is low and just needs to be refilled but then I remembered the issue with the heat as well. So I turned the truck off and restarting it worked and then the ac started working perfect for about 15 mins of driving then all the sudden went back to hot air. And not just ac turned off and blowing normal air temp air, I mean hot air as if the heater was turned on.

It doesn't matter what speed I drive either, I could be going freeway speeds with plenty of cooling to the condenser or I could be parked out in the driveway and the climate control is acting all funky. If I was having just issues with the AC then it would be a lot easier to figure out but its acting up with the ac and the heater. Sometimes it works and sometimes it does the exact opposite.

Is this maybe a cabin temp sensor issue or the climate control unit itself?

chiph9

Run the A/C system diagnostics (do a search here) when parked outside. I suspect you have one or more blend door actuators that have gone bad.

Chip H.

UncleRico

iTrader: (6)

OK perfect I will try that out and see what happens. Does this also test the heater system as well? Or is there a different test for the heater? Because my problem is ac and heat. If I play around with the temperature adjustment it will eventually go back to normal but heat and cold is affected by this bug Im having.

chiph9

The diagnostics will test the blend doors which control the temperature by directing airflow either through the heater core, or through the A/C fins. By messing with the controls you're probably freeing the door/actuator up allowing it to move. Temporarily.

If you pass the A/C diagnostics, something else to check would be the thermostat and the water pump - a bad thermostat (stuck open) can cause the engine to run cold and a bad pump will cause it to run hot - but you won't get much coolant flow through the heater core so you feel cold inside the cabin.

Make sure you're running the Toyota Long-Life coolant (it's red in color). There are aftermarket alternatives, but if you're having system problems it's best to eliminate external potential causes of problems. It should be changed every 3 years, btw.

Chip H.

UncleRico

iTrader: (6)

So I ran the diagnostic and everything checked out with no errors. Again over the weekend I was trying to run the heater but cold air was blowing out. After running the temp all the way down and then all the way up a few times it started to work normally again. Then later in the day I ran the a/c and everything was working normal but then it was acting as if you turned off the a/c button. It was blowing out "coolish" air but you could tell by the smell and the temp of the air coming out that the ac wasnt working properly. I was driving so I wasnt able to see if the compressor was engaged so still not sure whats going on with either cases.

I will check the coolants as you mentioned too.

Ike66

I am having a similar issue with both heat and a/c it works fine for the first 30-40 minutes the starts to fail. In the winter it blows hot heat for a while then fades away and the cabin temperature drops and with Wisconsin winters heat is a must. Then in the summer the a/c blows cold for about the same 30-40 minutes then fades next thing you know it’s hotter than #%=? in the car. Normally not an issue for me because my commute to work is short it’s only when I head out of town for a distance.