Climate Control Diagram?

NHTacoma · 03-04-2003, 08:18 AM

So I've been pulling my hair out trying to figure out why my heat is so weak (99 Tacoma 2.7). The engine operates at normal temperatures. I replaced the T-stat, checked the heater control valve, and had the whole system flushed, including a back flush of the core. None of this made a big difference.

Now I've made a new observation: The heat coming out of the floor vents is much warmer than the stuff coming out of the dashboard vents. I wonder if the air is bypassing the core somehow, with the dashboard vents getting more of the bypassed air.

I'm hoping someone out there has a diagram of the ductwork that they could provide me so I can see if this is possible or likely. I'd really appreciate it...its pretty damn cold in New Hampster.

Thanks,
Tom

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DH6twinotter · 03-04-2003, 10:30 AM

While I don't have a diagram of your ductwork, I do have a bit of an idea for you. Is your defroster jambed on somehow? Like the setting for defrost and floor boards might be stuck somewhere under the dash. Is there hot air coming out of the defroster vents? I dunno, but thought I'd mention it.

Well, I suppose that really isn't an answer to your question, but thought I'd say something anyways.

have fun.

DH6twinotter

NHTacoma · 03-04-2003, 12:44 PM

Thanks for the idea. The dampers all seem to be behaving normally. Air comes from where its supposed to.

I had thought that maybe my air conditioner was stuck on because that would explain all of the symptoms I'm having, but the compressor doesn't seem to be turning at idle. I need to check it again once the engine has warmed up and with the engine revved because it might be that when I checked it the first time the evaporator was too cold to signal it to turn on, or the clutch might only be engaging at higher rpm. I'm thowing punches in the dark at this point.

Still, anyone with diagrams who could help me out would be great.

Thanks again,
Tom

DH6twinotter · 03-05-2003, 08:05 PM

Here's a diagram I ran across in my haynes manual. Hope it helps. See attachment.

Have fun.

DH6twinotter

NHTacoma · 03-06-2003, 04:54 AM

Thank you very much. I really appreciate the effort. I'll see if I can correlate the diagram to what I find in the car.

Thanks again,
Tom

DH6twinotter · 03-06-2003, 06:41 AM

Quote:

Originally posted by NHTacoma
Thank you very much. I really appreciate the effort. I'll see if I can correlate the diagram to what I find in the car.

Not a problem. That's why we are here. To help our fellow Yota owners.

You know, I got thinking that that is a diagram for 89-95 trucks and 4Runners. I'm not sure how close it is to your '99. I would think it is pretty close though, but just thought I'd point that out.

Have fun.

DH6twinotter

BTW, Completely off topic, but I noticed in your sig that you have an 88 Audi 90. Has it been a good car? I got very close to buying a 93 Audi 90 CS. Loved that car. I figured parts would be really $$, so I didn't get it. :cry:

Alstaz · 03-06-2003, 09:01 AM

Just as a note. it is a common misconception that the AC system will only push cold air. It can be used in conjuction with your defrosters and warm air to clear fogged windows etc. So I don't think that the AC is necessarily the problem. HTH

Al

NHTacoma · 03-06-2003, 10:13 AM

Here's the story on the Audi. It belonged to my sister, who was the 2nd or 3rd owner. She bought a new car and gave the Audi to me when my car crapped out and I needed something for a month or so while I fixed my car. When I took it from her, it had 212K miles and a bunch of minor problems, but ran well. I drove it for a while, then it sat for a while, then I wound up with a girlfriend who needed a car but couldn't afford one, so I let her take it, then she crashed it into a tree, I fixed it up good enough to drive, and she's been using it ever since (though we've broken up...ain't I a nice guy?). A bunch of new problems have ocurred in that time. My basic impression is that the drivetrain will last forever, but that the secondary systems (cooling, electrical, body mechanical) are garbage. You can expect a whole bunch of small problems to drive you crazy, but the cars will keep on trucking forever. One of my best friend has a '90 quattro coupe, and he's had a bunch of small problems too...but its never stranded him.

As to the AC, on my truck the defrost setting on the air damper control signals the AC to turn on to fascilitate defrosting. My thought is that either that switch, or the main AC switch, is stuck on. That would explain why the heater isn't blowing as hot as it should be and also why my mileage is bad. I've looked at the compressor while the car idled and it wasn't turning, but the car was cold and it was cold outside, so the thermostat in the evaporator might have been too cold to signal it to turn on. Its a long shot, but its worth another look.

Thanks again, guys.
Tom

03-04-2003, 10:30 AM	#2 (permalink)
DH6twinotter Contributing Member Join Date: Oct 2002 Location: Charlotte, North Carolina Posts: 1,676	While I don't have a diagram of your ductwork, I do have a bit of an idea for you. Is your defroster jambed on somehow? Like the setting for defrost and floor boards might be stuck somewhere under the dash. Is there hot air coming out of the defroster vents? I dunno, but thought I'd mention it. Well, I suppose that really isn't an answer to your question, but thought I'd say something anyways. have fun. DH6twinotter __________________ ------------------------------------------------ 1990 4Runner: SR5, 2wd, 3.90 rear, 3VZ-E, auto. 15x8 MT classic II rims, 31x10.50 Bridgestone Desert Duellers ($50!), Cobra CB, 3' firestick Planned stuff: Pre-runner light bar with Hella 500s, small lift Stuff I'd do if I went crazy: SAS, 7mgte or 1UZ swap, and as much offroad goodies as $$ will allow.

03-05-2003, 08:05 PM	#4 (permalink)
DH6twinotter Contributing Member Join Date: Oct 2002 Location: Charlotte, North Carolina Posts: 1,676	Here's a diagram I ran across in my haynes manual. Hope it helps. See attachment. Have fun. DH6twinotter Attached Thumbnails __________________ ------------------------------------------------ 1990 4Runner: SR5, 2wd, 3.90 rear, 3VZ-E, auto. 15x8 MT classic II rims, 31x10.50 Bridgestone Desert Duellers ($50!), Cobra CB, 3' firestick Planned stuff: Pre-runner light bar with Hella 500s, small lift Stuff I'd do if I went crazy: SAS, 7mgte or 1UZ swap, and as much offroad goodies as $$ will allow.

03-06-2003, 04:54 AM	#5 (permalink)
NHTacoma Registered User Join Date: Feb 2003 Location: Near Manchester, NH Posts: 14	Thank you very much. I really appreciate the effort. I'll see if I can correlate the diagram to what I find in the car. Thanks again, Tom __________________ '99 Tacoma 4x4 Ext Cab, 2.7 (Kelly) '93 Porsche 968 Coupe (Ashley)

03-06-2003, 09:01 AM	#7 (permalink)
Alstaz Registered User Join Date: Feb 2003 Location: Madison, WI Posts: 60	Climate control Just as a note. it is a common misconception that the AC system will only push cold air. It can be used in conjuction with your defrosters and warm air to clear fogged windows etc. So I don't think that the AC is necessarily the problem. HTH Al __________________ Al Florence TLCA Member 1999 4Runner Highlander - Leather Int, Black Pearl Emblems, SAWs, Downey / Bilsteins, 285/75/16 Bridgestone Dueler Revos, Kenwood Excelon System, Grill Mod, Deckplate, ISR Mod... 1969 FJ40 Land Cruiser 4" 33X12.5 BFG Muds 1971, 1978, 1979 FJ40 Land Cruisers 1997 Collectors Edition Land Cruiser (OME, 285 MTs, Nav system...)

03-06-2003, 10:13 AM	#8 (permalink)
NHTacoma Registered User Join Date: Feb 2003 Location: Near Manchester, NH Posts: 14	Here's the story on the Audi. It belonged to my sister, who was the 2nd or 3rd owner. She bought a new car and gave the Audi to me when my car crapped out and I needed something for a month or so while I fixed my car. When I took it from her, it had 212K miles and a bunch of minor problems, but ran well. I drove it for a while, then it sat for a while, then I wound up with a girlfriend who needed a car but couldn't afford one, so I let her take it, then she crashed it into a tree, I fixed it up good enough to drive, and she's been using it ever since (though we've broken up...ain't I a nice guy?). A bunch of new problems have ocurred in that time. My basic impression is that the drivetrain will last forever, but that the secondary systems (cooling, electrical, body mechanical) are garbage. You can expect a whole bunch of small problems to drive you crazy, but the cars will keep on trucking forever. One of my best friend has a '90 quattro coupe, and he's had a bunch of small problems too...but its never stranded him. As to the AC, on my truck the defrost setting on the air damper control signals the AC to turn on to fascilitate defrosting. My thought is that either that switch, or the main AC switch, is stuck on. That would explain why the heater isn't blowing as hot as it should be and also why my mileage is bad. I've looked at the compressor while the car idled and it wasn't turning, but the car was cold and it was cold outside, so the thermostat in the evaporator might have been too cold to signal it to turn on. Its a long shot, but its worth another look. Thanks again, guys. Tom __________________ '99 Tacoma 4x4 Ext Cab, 2.7 (Kelly) '93 Porsche 968 Coupe (Ashley)

03-04-2003, 12:44 PM	#3 (permalink)
NHTacoma Registered User Join Date: Feb 2003 Location: Near Manchester, NH Posts: 14	Thanks for the idea. The dampers all seem to be behaving normally. Air comes from where its supposed to. I had thought that maybe my air conditioner was stuck on because that would explain all of the symptoms I'm having, but the compressor doesn't seem to be turning at idle. I need to check it again once the engine has warmed up and with the engine revved because it might be that when I checked it the first time the evaporator was too cold to signal it to turn on, or the clutch might only be engaging at higher rpm. I'm thowing punches in the dark at this point. Still, anyone with diagrams who could help me out would be great. Thanks again, Tom

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