Toyota Sienna Forum - siennachat.com banner
1 - 12 of 12 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
Hey folks,

My 2004 Toyota Sienna LE minivan won't blow cool air when the A/C is on. Had this problem last summer, but replaced the fuse/relay under the hood and it blew cold through the last couple months of summer. Now here again this summer, and it's blowing basically outside temperature air, which isn't pleasant in 95 F.

The previously mentioned relay/fuse is still in good working order, the freon is charged to recommended capacity, and the compressor kicks on immediately when the interior dial is switched on - but still no cold air. ???

Am I missing something - what else could be the issue?

Also, but hopefully unrelated, but the AC/heater blower fan for the front seats only works when turned on high - not on any lower settings. ??

I'm grateful for any insight you all are willing to offer. Thank you in advance.
 

·
Registered
2006 LE
Joined
·
1,677 Posts
See what the pressures are when the system is operating. You will of course need gauges to be hooked up to both the low and high side of the system . Also the resistor block that controls the speed of the blower fan may be faulty hence the reason for only getting one fan speed.
 
  • Like
Reactions: 307sienna

·
Super Moderator
Joined
·
348 Posts
Have a read through this lengthy thread and see if there's anything helpful: 04 A/C problems
 
  • Like
Reactions: 307sienna

·
Registered
Joined
·
559 Posts
Hey folks,

My 2004 Toyota Sienna LE minivan won't blow cool air when the A/C is on. Had this problem last summer, but replaced the fuse/relay under the hood and it blew cold through the last couple months of summer. Now here again this summer, and it's blowing basically outside temperature air, which isn't pleasant in 95 F.

The previously mentioned relay/fuse is still in good working order, the freon is charged to recommended capacity, and the compressor kicks on immediately when the interior dial is switched on - but still no cold air. ???

Am I missing something - what else could be the issue?

Also, but hopefully unrelated, but the AC/heater blower fan for the front seats only works when turned on high - not on any lower settings. ??

I'm grateful for any insight you all are willing to offer. Thank you in advance.
Blower fan only working on high is typically the final stage resistor. I have heard this is a massive pain on Toyotas, but I haven't done this one personally. When a coworker had the blower issue (in a Toyota truck), I said the same thing and he said his guy checked it out and said it wasn't that, but it was the actual climate control blower switch which required a junkyard part and lots of labor.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #5 ·
Thanks so much for the help guys.

I changed the cabin air filter, which helped a little. Is it worth checking the AC evaporator to make sure it’s not clogged? If so, any clues as to where it is? LOL I’m not particularly familiar with the mechanical side.

Also, another big question I have is: why does it blow cooler air on the passenger front side but then significantly warmer air on the driver front side?

I checked the blend door actuator and it is working properly... But now I’m a little stumped.

Thoughts?
 

·
Registered
2006 LE
Joined
·
1,677 Posts
Also, another big question I have is: why does it blow cooler air on the passenger front side but then significantly warmer air on the driver front side?
This happens because the freon level is low. You will need to add freon via the low side of the system. This happened to me when I had a slow leak in the condenser , a radiator looking panel , located in front of the radiator. Sometimes one 12oz can of 134A freon is enough , sometimes two depending on how much has leaked out. If the leak is slow a recharge may last up to 3 months , perhaps more. A rough guess as to when the level is somewhat ok is when the temperature from the driver and passenger side is about the same. Finding the leak and repairing it will be the best thing to do. For me it was a crack in the condenser on the upper left side which was hard to see but I did , during the installation of a transmission cooler that required the front bumper to be removed. The spot where the leak was will appear dark and oily. Your leak may be in a different location in the system.
 
  • Like
Reactions: SilverMachine

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
OK, but I already checked the pressure and topped off the freon ...? The freon lines underneath the hood get nice and cold just after turning the vehicle and AC on. After checking the system I have no known leaks and the freon system itself seems to be up to snuff.
 

·
Registered
2006 Sienna XLE with NAV
Joined
·
404 Posts
I experienced weak a/c in my 06 sienna a few years back. My mechanic did a complete system vacuum and refill for me. I will ask him do it again next week since I start experiencing weak a/c again. Is it possible that there is air in your a/c system?
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #9 ·
Thanks for sharing your experience. As far as I know, I don’t have air in my Freon system - But I honestly don’t know how to be sure?
 

·
Registered
2006 LE
Joined
·
1,677 Posts
The freon capacity in the system is about 2.5 cans of 12ozs 134A. If the system is still warm on one side and coolish on the other it still needs a bit more freon. That has been my experience. The first can you put in will have a minimum effect on the air temperatures coming the vents , initially. Its when you put the second can in that you will feel the difference. How many cans did you put in? What pressures are you getting?You may also want to cycle the mode selector through the various positions and note the changes through the different vents. When charging all doors should be open and select max cool on the temp selector.
 

·
Registered
Joined
·
1 Posts
Hello I know this post was in 2014. However, I decided to update this forum since this is probably the 2nd time that I will be forced to dismantle the dashboard of my wife's 04 Sienna LE and the 3rd time overall for the life of the minivan, to fix its seemingly timed a/c not cooling when needed the most, problem popping up when it is 112 degrees in SoCal. For some reason I found the failure mostly generating from a stuck expansion valve, with the fix as not only finding the leak as I put a dye on the second fix, but replacing the condenser, expansion valve and compressor and flushing the a/c hoses as well as the evaporator. While both times I was successful in bringing cool air back, it was not as long as I expected--1st fix was done in 2014; second was 2018 when we used the minivan on a West Coast to North East Coast road trip, when I was forced to purchase a stock model specific Denso compressor because I thought the replacement compressor's a/c clutch was not engaging. I kind of agitated it by pressing on the clutch and it worked and has been working great since then--until this early summer when I noted hot and cool air blowing when the a/c was on!!! A couple of weeks later its failure was sealed when radiator fan motor stopped working. Just like that. I agree that solutions to a Toyota a/c problem is by trial and error as in my case. Did what people here who shared their experiences, had done. From replacing o'rings, checking hoses for leaks, I spent a great deal of time trying to find the problem. And most of them I solved in flying colors. My concern was that the solutions were short lived. And these Toyota expansion valves when they clog, they clog big time, from my latest discovery of its condition. It was not only stuck but clogged that no matter what I did could not convert liquid gas to cool air through the evaporator, and aggravated by a seized expansion valve and stuck hex bolt. And boy I was forced to grind it with my dremel because it was seized, stuck and would not move even with heat. Finally I was able to remove it today but it cost me my evaporator since I forced it out so much so that the suction and discharge connector to the suction and discharge hoses from the firewall was ripped off of its spot. Be careful. Don't do what I did. Compared to an old lady, her bones are brittle! I am just disappointed because I thought it was a durable fix! Now I have to remove the dashboard with the hope that I can just pull the passenger side of the evap housing by removing the screws! That's a long shot. The good thing is that the 3rd compressor, Denso still, that I purchased as a replacement in 2018 is still with me and for the heck of it, I will replace the stuck compressor since I need it. I was getting lazy with not replacing the compressor, thinking that it was only the a/c clutch that was causing the problem. But considering that I am replacing all of them with my stock parts, no overhead involved, and will flush and vacuum it at least 2 times for 1 hour periods, before charging it with R134a, might as well do it. Doing this ain't no fun, as it pulls away a lot of time from you, but if you are seeking understanding applied science then DIY can help you with that. And so tomorrow, my goal of replacing the evaporator begins. Hope I can finish by the end of the day while still managing to vacuum the a/c system and charge it while putting the dashboard back in place.
 

·
Registered
2006 LE
Joined
·
1,677 Posts
If it is just the evaporator that you will be replacing there is a shortcut you could do without having to take apart the entire dash. Some cutting is involved . See this discussion particularly the post by member Kazsano
 
1 - 12 of 12 Posts
Top