Venting on my Vent

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sebsi
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My tercel:: 1984 SR5 4wd

Venting on my Vent

Post by sebsi »

Hi, first time post for me. Got my 84 about a month ago.

The vent does not vent. No matter what the setting or outside air temp, warm air blows. So if it's 80 degrees outside, the vent does not allow cool air in the car (on the freeway, etc). I saw some posts about the Cool/Warm control actually controlling two flaps, but the cable I found after removing the glove box only seemed to control one.

And, after digging around under the hood, I've found what appears to be the coolant flow control valve, which I had never heard of until browsing this forum. The cable goes into the firewall into the passenger compartment, but how is it controlled? I noticed that if it's open, the heater won't heat, and I'm wondering if this has something to do with the vent issue.

Thanks from a noob!

sebsi
hberdan
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My tercel:: Sold my 1987 Tercel Dlx 4x4 Wagon but miss driving it everyday. I don't miss working on it, though.
Location: Colorado!

Re: Venting on my Vent

Post by hberdan »

The coolant heater control valve (FSM calls it the water valve) is opened and closed mechanically by the cable attached to the temp control lever on the heater console. All the way to the right with that lever, into the red zone, opens the valve. moving the lever to the left closes the valve. At least, this is what is supposed to happen. On these older cars, the cables sometimes have stretched, or possibly broken or disconnected. If you're not sure if the valve is opening or closing, have a friend sit in the car and operate the temp lever while you watch to see if the valve opens and closes.
These valves sometimes get stuck. A bit of light oil may help. You may have to manipulate the valve lever while your friend opens the temp lever a few times to work it if it's been stuck for a while. If the cable does not move it might be disconnected or broken.
The valves are easy to replace but are pricey, about $70 each iirc.

As far as the vents go, on my 87, the vents next to the driver and passenger doors can be opened and closed with a little wheel next to the louvers. Sometimes they close by themselves. Gremlins, maybe? Check yours.
As I remember, my 84 and 86 did not have those things, all you could do was aim the louvers.
Last edited by hberdan on Tue Jul 13, 2010 8:23 pm, edited 2 times in total.
"I'm high on the real thing: Powerful gasoline, a clean windshield, and a shoeshine."
sebsi
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Posts: 24
Joined: Sat Jul 10, 2010 2:40 pm
My tercel:: 1984 SR5 4wd

Re: Venting on my Vent

Post by sebsi »

Thanks re: the coolant valve. I'll check it right away.

By "Vent" I mean the vent setting on the heater control panel. The controls work fine (i.e. when set to "Vent" air blows out the vents; when set to "Def" it blows where it should). However, this air (vent or otherwise) is never cool. I suspect that the "Cool/Warm" control flap never fully closes allowing truly cool air in. Any way to check this?

sebsi
hberdan
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My tercel:: Sold my 1987 Tercel Dlx 4x4 Wagon but miss driving it everyday. I don't miss working on it, though.
Location: Colorado!

Re: Venting on my Vent

Post by hberdan »

There are already some other posts on the forum regarding heater control vents and flaps, etc. You're going to have to search those out, then be prepared to squirm around under the dash and column to find the right cable controls.
Unfortunately, the FSM does not have much info on the heater controls, but there are a few diagrams that may help.
"I'm high on the real thing: Powerful gasoline, a clean windshield, and a shoeshine."
sebsi
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My tercel:: 1984 SR5 4wd

Re: Venting on my Vent

Post by sebsi »

I'll do some research. I checked my coolant valve and it's not controllable by my "Cool/Warm" level, and the heater works fine. I assume this means its stuck open. Would this explain the lack of cool air when set to "Cool"?

sebsi
hberdan
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My tercel:: Sold my 1987 Tercel Dlx 4x4 Wagon but miss driving it everyday. I don't miss working on it, though.
Location: Colorado!

Re: Venting on my Vent

Post by hberdan »

Yep. Perhaps if you disconnect the cable at the heater valve in the engine compartment you can manipulate the interior temp lever to see if the cable moves--if it does, then the heater valve is probably stuck open. You might be able to return the valve to service by lubing that scissors-like cable attachement point, and trying to get the valve to open.
Also think about squirting some lube into the cable sheath.
On one of my Tercels I never got the old valve to work and had to replace it. Might be able to find a replacement in a 'salvage yard if there is one near you. Otherwise you'll have to either buy a new one from a Toyota dealer, or let it run as it is. Having it stuck open, imho, is a lot better than having it stuck closed! At least in the summer you can open the windows to let out the heat. In the winter, better to have lots of heat than none at all. Plus having the heater operating helps keep the engine temp under control if your radiator is older and not doing such a good job.
Of course, I live in the mountains. If you live in a hot climate I'd fix it.
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sebsi
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My tercel:: 1984 SR5 4wd

Re: Venting on my Vent

Post by sebsi »

OK, problem solved. I can manually open/close the valve no problem but the cable is non-operational. When open, I get no cool air because (obviously) it's as if the lever is set to "Warm". If I close it, it's as if it's set to "Cool" and I get what I expect: cool, "outside" air.

I've traced the cable housing from the interior firewall to the control panel but can't see/feel from there. Any idea if it's connected at the level itself, or up where the cable from the level connects to the interior flap in the heater assembly?

I'm in the mountains, too (7000 ft in the Front Range, CO), so sure, heat is better, but I'm driving to AZ in a month and need some cool airflow!

seb
hberdan
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My tercel:: Sold my 1987 Tercel Dlx 4x4 Wagon but miss driving it everyday. I don't miss working on it, though.
Location: Colorado!

Re: Venting on my Vent

Post by hberdan »

Check out the online FSM and other posts; iirc there are some good photos of the arrangements. Worst case--stop the car, open the hood, adjust the valve, continue on!

https://tercel4wd.com/forums/viewtopic.php?f=7& ... rol#p39409
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dlb
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My tercel:: '87 sr5, '83 dlx parts car
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Re: Venting on my Vent

Post by dlb »

sebsi wrote:Any idea if it's connected at the level itself, or up where the cable from the level connects to the interior flap in the heater assembly?
hey sebsi. i'm not sure what you mean by this but have you removed the stereo and center dash stuff to get right up in the heater controls? i've removed/replaced a few of these and found it's easier to take out the countless screws than fight blindly with the cramped internals of the dash area. have you tried lubing the cable? if that doesn't work i would just replace the entire heater control unit. it's not a complex job and can be done in as little as an hour, and i think i've found units at the wreckers for $20 or $25.

good luck!
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ARCHINSTL
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My tercel:: Goldie is a 1986 SR5 attualmente con Weber/also owned the first T4WD in STL in late '82
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Re: Venting on my Vent

Post by ARCHINSTL »

What hberdan mentioned about takza's link (better than the FSM):
Look at waynehoc's photos a bit down in this thread - XLNT!
https://tercel4wd.com/forums/viewtopic.php?f=4&t=1743
My heater valve does not open or close fully, despite fiddling with the cable and its casing "anchors;" so I just unhooked the cable and manually move the valve to full open or close (I do leave it hooked up for those cool Springs and warm Autumns, though).
Tom M.
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hberdan
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My tercel:: Sold my 1987 Tercel Dlx 4x4 Wagon but miss driving it everyday. I don't miss working on it, though.
Location: Colorado!

Re: Venting on my Vent

Post by hberdan »

As a follow-up, my own heater control lever wasn't working too well this last winter, either, so I got in the habit of just leaving the control lever all the way over to the warmest setting, as it was difficult to reset.
Yesterday in the warm sunshine it took about ten minutes to disconnect the cable from the heater valve, clean off the valve, lube the cable by spraying some electrical-grade silicone spray into the cable sheath, reattaching the cable to the valve and checking for function. Lo and behold, restored.
"I'm high on the real thing: Powerful gasoline, a clean windshield, and a shoeshine."
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