Issue with interior air (heat/cold) fan. Any ideas?

Hey all!

I posted on this a while ago (maybe 2-yrs) and didn't hear much for responses. I'm curious if anyone has come across this issue and come up with a fix.

I've had this problem, extremely intermittantly, over the last few years. I put a lot of time in the mountains, and it seems to be releated to altitude. The problem occurs when I get ~9,000' in elevation, my fan simply ceases to function for hot or cold air. If I remain above 9,000' the problem will remain even after I turn the vehicle off. It tends to stay off through the duration of my trip, and typically turns back on randomly around 7,500'.

I've noticed this problem getting worse over time. It used to be maybe one out of three trips that I'd have a problem, now I can count on it every time I go up. This weekend, it went out just like clockwork... except... it didn't come back on at 7,500' this time. I've been back in Denver (5280') for two days, and still no air.

Any ideas? I don't know enough about how the fan system operates to even take a guess at why altitude would have an effect. I'd like to get this issue resolved, especially since we have a baby on the way and I will need to be able to regulate temperature for road trips without worrying about this issue. Any help is appreciated, and feel free to ask if you think I may have left out any critical info.

 

I'm with you, more than slightly confused.

Does it run off of any vacuum?

I should also note, this happened to my wife's Explorer a few years back, and my buddy's S-10 every time that he drove up this year.

 

Haha, that's what I'm here for!

I highly doubt I'm the only one to run into this issue... seems fairly common since all three of these vehicles have had the problem. There has to be some kind of trophy involved if I've found an issue that's never been uncovered on TW as of yet

 

Thats the craziest thing I have ever heard of. Does the fan not turn on at all? Or is it on but nothing coming out? Rep for you for blowing my mind up!

 

Hmm... guess it could be either, not sure there'd be any way to tell a difference.

I can crank the dial all the way up, hot or cold, and nothing comes out. I can turn from defrost to hi/lo ducts and everything in between, and no air will come out. I can turn the A/C on, and the light illuminates, but no air blows from the ductwork.

I usually just leave the fan on high, and at some point on my way home, it just starts blowing... but it seems totally random! I've actually had it turn back on at 9,000', only to turn back off.

This problem has never occured in town or on long highway trips in the flat-land.

 

There was a thread not too long ago about guys complaining that their air wasn't blowing cold but there was still air moving from what I can remember.

 

Oooh, turbo-pun!

Didn't catch it the first time. Nice work!

 

Typically, yes...

I haven't for the last two days, however... but this is the first time in 3-yrs of having this issue that I've not gotten power back to the fan.

Maybe it finally crapped on me!

 

I'm just womdering if the fan is on, can you hear the fan on? I'm not sure if the selector to make it blow defrost or on your feet for example is vacuum. If that is maybe the altitude change is messing up the vacuum for that and the fan might just be blowing air into Tacoma heaven and not into the cab. Someone might know more about how the selector works. I know its vacuum on other autos I have owned.

 

Alright, great... we've nixxed the vacuum idea.

I'll give those documents a better look after this weekend. I'm headed up to the mountains after work today, and won't be back until Sunday. I'd like to test it now since it's not working currently, but just can't get to it today.

I'm actually happy to hear that it's an electrical component. Once I dial in on the faulty component, I may be able to replace it and kill this issue!

Thanks for the brainstorming, fellas!

Oh yeah, and the fan is definitely not on. It's as though it's getting no input from the controls.

 

i've had this happen to me a few times as well but not in the mountains, i would lose blower functions for the day and the next day they would be back on

 

Thanks, was not sure about that. OP keep us posted,would really want to know why it is doing that. Is it a long trip for you? Maybe after a long trip the switch heats up and loses contact some how. Longest I have been on a trip is about 2 hours steady and never had this issue. But it wasn't in the mountains.

 

Nope, but that's valuable information!

The trip is ~2-3hrs from Denver. I'm over 9,000' every time it goes. Most importantly, after the vehicle sits overnight, it still does not work in the morning. The fan will kick back on (typically) about an hour into the trip home.

I've driven 18-hr trips without an issue, never going over a high mountain pass.

 

Interesting, keep us posted. Specialy if you do what 98 said and check those things. Might actually be a science experiment. Something to do with pressure and less o2. Who knows.