Trick for getting heater control unit out - Toyota Nation Forum : Toyota Car and Truck Forums

feliks · 12-04-2007, 08:40 AM

Is there one? For a gen 3, seems like the clip for the temp control is really weird to remove anyone got tips???

tarbasd · 12-04-2007, 12:10 PM

I did remove it once, and I kind of remember it wasn't trivial. I think you have to take out the radio. The Haynes manual describes it nicely, I'll try to remember to look it up when I get home.

noodlerooney · 06-22-2008, 08:42 AM

I'm in that situation now, my heater control knob has seized, broken cable?. I have the feeling that I must release the cable from the heater control valve under the hood (with the funky clip, near the firewall, tied into the heater hoses) before I'll be able to pull the control from the dash. This cable is not the one for the air recirculation which also must be disconnected. And I have pulled out the radio for the extra room to work. I noticed that the FSM mentions nothing about disconnecting the electrical connections either, only the air recirculation cable.

xtremeskier97 · 06-22-2008, 03:15 PM

If you remove the heater control knob there is a screw behind it that must be removed to get the dash unit out of the way. THEN you can disconnect the cable from behind it.

noodlerooney · 06-22-2008, 03:33 PM

So after removing the screw behind the heater control knob, the heater control "faceplate" can be pulled away, leaving the "guts" of the temperature control behind? What's left behind can be removed much easier now? Thanks for your reply. I tried this already and met with some resistance and stopped for fear of breaking something. Will pull harder now.

xtremeskier97 · 06-22-2008, 08:40 PM

Quote:

Originally Posted by noodlerooney

So after removing the screw behind the heater control knob, the heater control "faceplate" can be pulled away, leaving the "guts" of the temperature control behind? What's left behind can be removed much easier now? Thanks for your reply. I tried this already and met with some resistance and stopped for fear of breaking something. Will pull harder now.

Yes...all of your assumptions are correct. After I removed the screw, mine was hard to get out as well. I took the butt of a screw driver and pushed it through.

noodlerooney · 06-23-2008, 06:15 AM

Good idea about the butt of the screwdriver used to push the stem through. I'll also try some quick hits to try to dislodge the assembly from the faceplate via the control stem. Thanks for all your help.
UPDATE: Got the unit seperated from the faceplate. The reason it needed the butt of the screwdriver was that there were 2 clips holding it on to the faceplace, upper left and lower right, the kind where the unit slides in with a male tab and clicks into female tabs. If you lifted the tabs, it would have come out without screwdriver butt. I now see that there are two (2) cables connected to this unit, 1 in the engine compartment connected to the heater hose valve and 1 in the passenger compartment connected to the heater radiator door. Push in cables for cold, pull out for heat. The cables seem fine, it's the unit that broke at the pivot screw. Ordered the part at Toyota, $50. USD.
UPDATE: I have determined that the cable going to the engine compartment heater control valve is indeed hanging up a bit, I will be replacing it. I'm sure this additional stress was the cause of the unit's failure at the pivot point. Maybe that's why they include this cable with the unit!

djb2 · 07-01-2008, 08:32 PM

I just encountered exactly the same problem -- the temperature control knob didn't have full travel, and made evil clicking noises when forced.

When I took the control unit apart I found that the housing holding the rear of the control shaft down had broken. This allowed a pinion to lift off of a bevel gear and skip teeth.
The root cause was almost certainly the heater valve control cable binding up in its sheath, which in turn put excessive force on the internal gears.

The coolant valve just on the engine side of the firewall operated easily once the cable end was removed, so that didn't contribute to the failure. You can test your valve by locating the valve on the firewall, releasing the metal clip that holds the cable sheath, and lifting off the eyelet end from the valve. The valve should open and close easily with just finger pressure.

To replace the control unit you need to remove the instrument cluster surround. To do this remove the radio surround, the part with the lighter socket. It is held with spring clips on the bottom and tabs on top. Pry the bottom out, and pivot the bottom edge towards the rear until the top pivots free. You can just let it dangle from the lighter wires.

You'll now see the two #2 Phillips head screws that were hidden under the bezel. Remove these two, and the two similar screws near the instrument cluster. Unclip the surround starting at the bottom, pivoting the bottom out to release the section on top of the instrument cluster. Once the surround is loose remove the four electrical connections from the dimmer, mirror control, clock and hazard switch. Each has a different connector shape so they can't be mixed up. Each connector has a different type of retaining clip, just to make it a challenge.

You can proceed with the radio in place, but it's much easier if it's moved aside. It's held by the four obvious screws. They are best removed with a 8mm driver, rather than stripping out the phillips head. You may just drop the radio down, leaving the wiring in place.

Pull off the heat control knob and remove the #2 head screw underneath. Lift the plastic retaining clips on top and bottom and pivot the rest of the HVAC panel to the right, leaving the temp control held in place by its two cables. This step is where unscrewing the radio gives you much-needed room. (The rest of the HVAC panel is held by the wiring and a third control cable.)

Now to remove the final connections to the temp control-- the cables. Remove the small black retainer from the blue cable eyelet end, and unclip that cable sheath from the control. Now, if you unclipped the water valve end, the whole control unit with black cable attached should pull from the dash.

It's trivial to unclip and disassemble the control unit, but you can tell if it's broken just by looking at the bottom. You'll see the cracked plastic around the pivot point.

Reassembly is mostly the reverse. The only trick is the black control cable. It slides into a white plastic sleeve that guides it through the firewall. But you'll have to "milk" it through the rubber boot on the engine side.