Inconsistent Cabin Air Output

I’ve noticed an issue with my new-to-me Tacoma where the cabin air flow from the vents is inconsistent. I’d say about 60% of the time it works as it should, but the rest of the time it feels like hardly any air is coming out of the vents regardless of what speed I set it too. Blower motor is working fine, changes speeds etc. I replaced it anyway just for kicks and it didn’t solve the issue. New cabin air filter had no impact either. What could be the problem here?

I should note that the cabin air filter I pulled out of it was pretty disgusting. I’ve also noticed that it leaves a pretty large water spot in my driveway after driving, more than I’ve ever noticed on other vehicles I’ve owned. Maybe that’s a normal Taco thing but possibly related?

 

The Tacoma A/C piss puddle is normal, it's a good idea to extend the drain hose from the fire wall so it isn't constantly leaking directly into your frame though.

As for the air flow, double check the plug at the blow motor isn't becoming charred or burnt it gets really hot at the plug and can become it's own resistor slowing down the blower fan.

Check the in flow resistor pack that is near the blower motor for the same heat indication melting etc and consider replacing it, they fail somewhat regularly yours may be on it's way out. I replaced mine with an aftermarket it failed in a few months got an OE and it's been okay for a while now but I have a PWM digital one in my Amazon cart if this one fails.

Pull up your hood louver and check that the outside air intake isn't blocked, if you have the intake set to outside and the intake is sealed the blend doors seal from drawing in cabin air so that could limit your flow.

Also check when in recirculate if the flow speed increases when you crack the window down, could indication your cabin pressure equalization vent(s) are blocked.

Squirrels and mice like to nest in both those locations on cars especially if they've been sitting for sale for a while.

Lastly replace your blower motor filter with a K&N reusable, they filter plenty fine (considered just 15 years ago cars were still being made with no A/C filter) but do flow a crap ton more air with the A/C system and they're much stronger meaning they don't deform if they get clogged and they can hold a lot more sand or has been my experience.

(I do not recommend K&N engine air filters, they do not filter better than stock nor do they provide any valuable benefit.)

 

Either someone has been down this road before, or they really know their air systems. Haha, thanks for all the tips. I guess I have more things to check!

 

I'm just a tinkerer/modder even I like fixing what ain't broke sometimes in the process I break it, then I learn.

I removed my rear seats in my Access Cab and put a gear rack back there instead, when I did that I was getting a lot of road noise from the rear bulkhead equalization vent, I ended up putting some foam insulation in there and I noticed when I would turn the fan on if I had it set to outside intake the pressure in the cabin would increase and fan speed would decrease unless I had a window down. I ended up removing some foam so the air could exit a little more freely, it helped but I'm balancing the pressure vs noise game now.

About to do a full sound deadening treatment on my truck to include redoing the foam in and possibly rerouting the rear equalization vent.


If none of that checks out, then come on back and we can poke at it some more.

 

So changing from outside air to recirculating air has no effect. Windows up or down has no effect. I went ahead and changed the intake air filter for kicks and that didn't have any impact either. I ordered a new resistor and pigtail to see if it solves the problem. I'm skeptical because the new blower seems to be functioning fine. It changes speeds and never seems to slow down. The only thing that changes is the amount of air coming out of the vents. If these parts don't fix the issue, I don't know what else it could be. Could something be clogged? I know next to nothing about AC units so I'm lost. I know an AC shop will tell me I need new everything.

 

Bad blower motor resistor typically means the blower only works on High. So I doubt thats your issue and you're probably just spending unnecessary money at this point replacing parts that seem to be ok.

You said the cabin filter was pretty bad. You might pull up the black plastic cowl and check that area out. Id be surprised if it was plugged enough to cause a problem, but they can collect junk and possibly rodent nests. This is a good thread on it showing pics, and also the screen mod itself.
https://www.tacomaworld.com/threads/cabin-air-intake-screen-mod.566441/

 

Is the recirculation door moving like its supposed to?
Pull your glovebox down and watch it while you operate the recirc button, it should be open with it on and closed with it off.

 

Yeah, I have no faith that the resistor and pigtail are the issue but I'm covering all bases. At least I'll be able to call it preventative maintenance.

Thanks for this link, time to read up!

 

Not sure but I'll check that. Thank you.

 

Could it be a dirty/clogged evaporator that a flushing and coil cleaning would fix? Anyone know if there's a procedure similar to this for 2nd Gens? https://www.tacomaworld.com/threads/diy-evaporator-cleaning.678272/

 

It could be but if it works good sometimes but not always I couldn't see it being that, once it's plugged it's plugged.
It would be difficult to clean the evaporator in a 2nd gen truck without pulling the HVAC case, on the 1st gens the evaporator was mounted in it's own box separate from the main HVAC housing and could be easily removed.
If it's had a cabin air filter in it it's whole life the evaporator shouldn't get very dirty.

 

Man, I hope you're right. I'd rather set my truck on fire than have to pull the dash.

 

Haha, exaggerating. Don't tell my insurance guy!

 

It will be our little secret... Shhhhhhh.

 

Just wanted to give an update for future researchers.

Today I replaced the resistor and the pigtail with the updated design. Part numbers 87138-04070 and 82141-04Q80. I wasn’t expecting the new to look so much different than the old, but it does.

Everything is working great right now. The old resistor looked pretty rough but the connector looked fine. It seems like the air flow is stronger on every speed than it was before, but that could be wishful thinking. I’ll give it some time before I consider it solved, but if is, we’ll know that a bad resistor can cause weak air flow and not just NO air flow.

 

UPDATE: Issue is not resolved and I am annoyed.

 

When the air changes is it coming out somewhere else like the floor or defrost vents?

 

Nope. Just weak air flow from wherever I have it directed to.

 

Have you checked the connector at the blower switch for melting or burning, those are known to have issues from time to time.
If that's not it and you say all the actuators are working properly I have no more ideas, I've never seen an intermittent airflow problem that wasn't a broken blend door, a bad actuator, or a problem with the blower.