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Discussion Starter · #1 ·
Hey gang -

I've looked through my Haynes manual, and searched; but didn't find anything. My truck is now producing very minimal heat; even after it is fully warmed up. The temperature gauge is reading in the normal position. Any ideas of what I should check for first?
 

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Make sure thermostat is not stuck open and the heater core is not clogged or damaged.
That's all I can think of.....I'm sure others will chime in with their experiences.
 

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If your thermostat is opening, then the next thing to check would be your heater valve. I believe it is located on the firewall (back wall of engine compartment). When you adjust your climate control knob (inside vehicle), you will be able to see the valve open and close (have someone turn the climate control knob while you are watching the valve move). If the valve appears to be working, place your hand on the outlet hose (the one going into the truck). It should be hot (once car is warmed up of course AND with climate control knob in Hot position). If it is cold, then the valve is stuck closed. If it is hot, then the valve is fine, and you likely have a blockage in the heater core.
 

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Meenkya, correct me if I'm wrong, but if the temperature is reading normally, then the thermostat would not be stuck open.
 

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Meenkya, correct me if I'm wrong, but if the temperature is reading normally, then the thermostat would not be stuck open.

I used to think that also...But
Had two fords that had the thermostats stuck open problem with normal temp readings.
 

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Check that you are not low on Anti-Freeze..

just did this with my wife's car.. she complained of no heat.. I would drive it around and it would be fine, then whammo.. the thermostat opened, and ice cold came pouring in. :eek:

With the truck cooled down, open the rad cap and check, the check the overflow to see if it needs to be topped up.
 

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Discussion Starter · #7 ·
Ok. I checked and the anti-freeze levels are fine.

I found what I THINK is the control wire/valve. It doesn't seem to move when the dial is changed from cold to hot. It seems to not move at all. It was stuck in the out/up position (the lever). When I pushed it in/down, the air became hot. I guess its ok to leave it like this until I can fix the problem? How hard is it to replace this cable? Is that pretty much definitely what my problem is?
 

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Check the cable is clipped into the holder. I got my new 06 home and on a drive i turned up the heat (not alot of resitance there for a manual dial - didn't know - new truck ). I turned the dial back and forth a few times and noticed out of the corner of my eye something moving by the passenger foot area. The cable had been knocked or something and fell out of the clip retainer. Worth checking.

Martin :)
 

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Discussion Starter · #12 ·
The cable is attached to the lever on the valve, but it just doesn't move; so either the cable is broken or the valve is stuck.

I can move the valve by hand and at least at this point I have heat; but I guess I need to do some more looking and see what is up.
 

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The temp dial on your A/C control panel moves a cable which moves the heater hose control valve. When you rotate the knob to "hot", the control valve opens up and lets hot engine coolant into the heater core. When in the "cold" position, the valve closes and keeps hot coolant out of the heater core.

OK....from what you describe, the valve under the hood is operating correctly, meaning that it moves freely when you use your hand. As previously posted, there is a problem with the cable assembly. The cable is attached to the A/C temp control knob on the inside and the heater control valve in the engine compartment. The first thing to check is that the cable is properly connected at both ends. The next likely problem involves the cable sheething. The actuator cable (the part that connects to the moving parts and actually moves) rides inside a sheeth. IF that sheeth is not securely mounted, the SHEETH will actually move instea of the cable. The sheeth will be mounted to a solid structure near the control panel, probably on the evaportator box.

I would remove the A/C control and inspect the cable and sheeth.
 

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Discussion Starter · #14 ·
So I took the dash cover off and checked out the other end of the cable connection. The dial side looked fine. So the valve side moves fine (by hand), and the dial side is moving the cable. There must be something wrong between the two?

Even better is that now I have no heat, even with the valve manually open! I have 250 miles left on my extended warranty, so I'm gonna take into the shop tomorrow.
 

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You may have a broken gear behind your hot/cold dial on the
hvac control panel. The heater control cable is attached to a worm
gear setup that is made of plastic and like most plastic parts that
are subject to repeated stress and are 6 or 7 years old, they break.

Remove the instrument bezel (if you are mechanically inclined). Lower
the hvac control cluster from its mounting bracket and check the center
worm gear for two control cables attached. My bet is that the cable coming
from the right (steering wheel side) is no longer connected to the worm gear.

Now for the fun part. If this part is broken, you will have to go to a
salvage yard and get another one (only a matter of time before IT breaks)
or fork over $300+ to Toyota for a new cluster - the broken part is not
sold seperately. If you decide to take it to the dealer for repair, keep in
mind how much just the part is and add a generous labor charge on top
of that.

If you want to do it yourself, you will develop a new appreciation for patience
installing the three control cables to the new cluster.

If what I described above is indeed what is wrong in your case and
you would like detailed instructions on how to fix it including SRS
concerns, let me know and I will "walk you through it."

dogger
 

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Hey gang -

I've looked through my Haynes manual, and searched; but didn't find anything. My truck is now producing very minimal heat; even after it is fully warmed up. The temperature gauge is reading in the normal position. Any ideas of what I should check for first?



If the engine is up to temp and the heater valve is working properly, try cracking open a rear window and see what happens. Every Toyota pickup I've owned ('91,'96,'06) responds well to that. Works with the AC too. Sounds Oakie (no offense to y'all out there) but these trucks are sealed pretty tight.
 

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Discussion Starter · #17 ·
If the engine is up to temp and the heater valve is working properly, try cracking open a rear window and see what happens. Every Toyota pickup I've owned ('91,'96,'06) responds well to that. Works with the AC too. Sounds Oakie (no offense to y'all out there) but these trucks are sealed pretty tight.

The problem isn't that no air is blowing, it is that COLD air is blowing.

Or, to quote Ron White

"Its not THAT the wind is blowin', its WHAT the wind is blowin'."
 

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Discussion Starter · #18 ·
FYI gang, I took it to the dealer this morning. The water valve had seized, causing the cable to break. Covered by the extended warranty. Got a free loaner vehicle as well. Can't complain.
 
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