Cold air on Passenger Side Floor - Has anyone figured it out? (1 Viewer)

[blklnamru]

Going to look into this once I get into DFW area tomorrow. It's about 32d out and we have the heat going with recirc. My sister is driving, so I got the chance to feel the effect first hand. I'm feeling ICE cold air coming into passenger footwell.

Can't figure it out, so blocked it off with a few tote bags for now.

 

[87warrior]

I recently discovered my 99 has the same issue. My wife said it is colder riding shotgun in the 100 than it is in my soft top TJ. I haven't dived under the dash to see what could be wrong. I did verify running the HVAC on recirculation mode greatly reduced the cold air blowing in, but did not eliminate the cold air.

I will keep my eye on this thread for some help and will post anything I find.

 

[SurfSwitch]

I'm so glad just about everything under the sun has been covered in this forum because this is currently driving me nuts. I'm taking out the entire interior next month for some sound deadening while I do my KISS drawer install, so hopefully I'll find something.

 

[ItGoesTo11]

I recently discovered my 99 has the same issue. My wife said it is colder riding shotgun in the 100 than it is in my soft top TJ. I haven't dived under the dash to see what could be wrong. I did verify running the HVAC on recirculation mode greatly reduced the cold air blowing in, but did not eliminate the cold air.

I will keep my eye on this thread for some help and will post anything I find.

I will be looking into this until I fix it. I have to wait a week or so as it's currently -10F here and my garage is not above freezing when it's that cold outside.
Once I can get into it, I have a borescope with a lighted end ready so I'm going to trace/follow all the entry points to see if it's mouse damage, a stuck flap or some other reason.

I'll get to the bottom of it soon enough and will post back here when I have some firm answers.

 

[Rip]

i had this problem but got the schematics and fixed it (actually I diagnosed and had my mechanic do the actual "work"). Flush heat exchanger. The air mix is solenoid controlled and the gearing breaks leaving just cold air......check into that. IIRC there is a separate one for the driver and passenger. The passenger side one is relatively easy to replace if that is your problem.

 

[ItGoesTo11]

i had this problem but got the schematics and fixed it (actually I diagnosed and had my mechanic do the actual "work"). Flush heat exchanger. The air mix is solenoid controlled and the gearing breaks leaving just cold air......check into that. IIRC there is a separate one for the driver and passenger. The passenger side one is relatively easy to replace if that is your problem.

Any chance you can post the schematics? That will help a lot.

 

[JETTIX2]

Bump to resubscribe to a thread I started several years ago because I've got a Hundy again

 

[Rip]

I got the schematics online. I don't have it but the following could be helpful. The servo gears mess up....this is a diy fix. Not necessarily the OP's issue but if the driver's side is warm and the passenger's side is cold, what else is it besides the mixture control. Mine is controlled electronically. If both sides are cold. I'd flush the heat exchanger and pray.

DIY Repairing Air Mix Servomotors - Club Lexus Forums

 

[87warrior]

I only found one front mix servo posted for the 100 series, 8710660120. There are two other servos listed, but I wager those are duct control.

Perhaps there are two issues coming up here. My 100 blows hot air from the floor duct on both sides. The issue is at highway speed there is also cold air pouring into the passenger side footwell, somewhere from the right side of the vehicle, which strangely is reduced when the hvac control is switched to recirculate mode.

 

[Koda]

I'm in the passenger seat going 70 through The Camas Prarie in Idaho where it's down to -9. My left foot is warmed by the floor heat vent. My right foot is freezing from the outside air flowing in below the glove box. Definitely speed related. I can feel a ways up behind the glove box and ioutside air is somehow blowing through there. Now I know what my wife has been complaining about. I hope one of you guys figures it out. Happy ski season!

 

[ItGoesTo11]

I will be looking into this until I fix it. I have to wait a week or so as it's currently -10F here and my garage is not above freezing when it's that cold outside.
Once I can get into it, I have a borescope with a lighted end ready so I'm going to trace/follow all the entry points to see if it's mouse damage, a stuck flap or some other reason.

I'll get to the bottom of it soon enough and will post back here when I have some firm answers.

UPDATE - SOLVED I investigated this issue and have found the problem and solution.

The cold air intrusion into the passenger footwell was caused by the replacement OE fan (non-OEM). The original Lexus OEM blower fan seals itself fully when mated to the ductwork housing and prevents cold outside air from entering the cabin prior to being heated.. However, the replacement VDO blower fan does not fully seal itself, there are three mounting "ears" for the three screws that hold the fan to the housing. One of those "ears" on the VDO replacement fan is more like a square "tang" and leaves a big gap for incoming outside air to stream into the passenger footwell. It does not have the molded design of the OEM Lexus fan and is instead flat stamped metal, hence the gap and the incoming cold outside air.

The "tang" points outward towards the passenger side of the vehicle and you can access the fan by simply looking under the dash where the passengers feet normally are. I used molding clay, available from any hardware store, to cover the "tang" and the gap it creates. The cold air problem is now solved.

I am also presuming everyone who has this issue replaced their blower fan at some point with a non-OEM fan, or the previous owner of the vehicle did. Look in this area and cover the gap with some sort of sealant and your problem will be solved.

 

[87warrior]

Thanks for your investigation @ItGoesTo11.

I cannot say if the blower is my culprit as I will check the seal tomorrow. I did look under my dash and noticed I still have, what I believe is the OEM blower...but I have been wrong before. You can make out "denso" in the foreground.

I verified the three blower motor mounting screws were tight when I first started searching for the cold air source. What I didn't do was verily the seal was still good. I know there is a tremendous volume of air being funneled into the fresh air intake when on the highway and it is easy to reason some of that air could sneak passed a poor seal.

 

[ItGoesTo11]

Thanks for your investigation @ItGoesTo11.

I cannot say if the blower is my culprit as I will check the seal tomorrow. I did look under my dash and noticed I still have, what I believe is the OEM blower...but I have been wrong before. You can make out "denso" in the foreground.
View attachment 1372244

I verified the three blower motor mounting screws were tight when I first started searching for the cold air source. What I didn't do was verily the seal was still good. I know there is a tremendous volume of air being funneled into the fresh air intake when on the highway and it is easy to reason some of that air could sneak passed a poor seal.

Correct, all the incoming outside air (when not in recirc mode) flows past the fan. So when it's 10 degree F outside, the air blowing past the fan is 10 degree F prior to being heated by the heater core and entering the cabin. If there are any leaks at the fan seal, the air will blow into the cabin onto the passengers feet.

I also sent my lighted borescope all the way up the incoming ductwork and traced the incoming air path back towards the fan, everything is as it should be. I also verified the activation of the "fresh/recirc" doors and they functioned properly also. The issue, for me, was most definitely a leaky fan seal, there is no other place for air to enter the cabin as the ductwork is all sealed, other than the fan opening.

Yours looks like an OEM-type blower, it has the molded square mounting "tang" I referenced. Some non-OEM fans, like the VDO unit I purchased, only have a stamped metal piece in that area as the mounting "lug" and for me, cold air was pouring in around that open area.

I would check the sealing of that fan to ensure you don't have a sealing problem. And thanks for the pic, it helps others to visualize the area I referenced.

 

[TheForger]

This is a good possible solution and excellent find @ItGoesTo11, but I don't see how this will help those of us who are having this problem on BOTH the drivers and passengers side foot wells. I will still go out and check the seals around that blower motor, but I'm looking for a solution to the cold air on my feet while driving as well. I have noticed the air I feel on the DS foot well seems to be speed specific but that's about all the investigating I've done. Will dig into it sometime in early January.

 

[JETTIX2]

Could it be from a poor lower windshield seal, allow air down the back of the dash and ending up being drafty in the footwells?

 

[ItGoesTo11]

This is a good possible solution and excellent find @ItGoesTo11, but I don't see how this will help those of us who are having this problem on BOTH the drivers and passengers side foot wells. I will still go out and check the seals around that blower motor, but I'm looking for a solution to the cold air on my feet while driving as well. I have noticed the air I feel on the DS foot well seems to be speed specific but that's about all the investigating I've done. Will dig into it sometime in early January.

Thanks and yes, it applies only to those complaining about cold air in the passenger footwell/wife complaining issue.

 

[unfast]

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[spikey]

'Cold air on Passenger Side Floor - Has anyone figured it out?'

Almost 4 years now, looks like the answer is "no".

 

[unfast]

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[ItGoesTo11]

View attachment 1372603 View attachment 1372604 View attachment 1372604 View attachment 1372605It appears mine is a interference fit with no gasket/weather stripping. Wife noticed in Northern Nevada at about 1* outside temp. Filled void with wax, will report back. Fyi screws on my 03 470 were t25 and there were 3.

Yes, thanks for the pictures, that's exactly the area I had the leakage (the square molded mounting "tang"). Except my replacement non-OEM fan (a VDO unit) doesn't have the molded square tang, it was a flat stamped piece of metal and cold air was pouring in around it.

I'll reiterate that I traced the entire air path with my lighted borescope and I could not find anything else amiss, and a test drive prior to the repair with a passenger showed the cold air pouring in from that square tang. Once I covered the void with molding clay, the leak stopped.