No Heat After Control Valve Replacement

[BogeyJH]

I recently replaced the leaking heater control valve (HCV) on my 94 LS 400.

I also have a problem with the valve control cable, which doesn't move when the climate control settings are changed. The cable was pretty stiff, so I lubed it and was able to move it in and out. But it doesn't move easliy and only about an inch.

I disconnected the control cable and set the HCV to the 2 o'clock and then 6 o'clock position. No heat with either setting.

I think the blend damper is functional. With the AC on and the control in AUTO mode, I can hear what is likely the blend damper move and the air flow changes from very cold to only cool when I raise the temperature setting from MAX COLD. At MAX HOT and with the AC off, the air from the vent is outside air temperature.

Is this a combination of problems or multiple failures?

Any input offered will be greatly appreciated.

[wwest]

I recently replaced the leaking heater control valve (HCV) on my 94 LS 400.

I also have a problem with the valve control cable, which doesn't move when the climate control settings are changed. The cable was pretty stiff, so I lubed it and was able to move it in and out. But it doesn't move easliy and only about an inch.

I disconnected the control cable and set the HCV to the 2 o'clock and then 6 o'clock position. No heat with either setting.

I think the blend damper is functional. With the AC on and the control in AUTO mode, I can hear what is likely the blend damper move and the air flow changes from very cold to only cool when I raise the temperature setting from MAX COLD. At MAX HOT and with the AC off, the air from the vent is outside air temperature.

Is this a combination of problems or multiple failures?

Any input offered will be greatly appreciated.

"so I lubed it and was able to move it in and out."

YOU moved it forcefully or you cycled the system from hot to cold so the blend door servomotor could move it..?

Latter is okay, if the former then you probably disconnected the cable at the blend door servomotor end. Blend door and water flow control are operated in parallel by the same servomotor. You may have even damaged the servomotor so that the motor internals work/move, but with no movement externally to the blend door or HCV cable.

[BogeyJH]

Thx wwest, I really appreciate your response.

Either way, it appears I need to gain acces to the blend door and servo motor connection.

I searched the forum for some info on access to the blend door and found this post from Ralph Newman.

This will likely help if I just need to re-attach the cable, but what would be involved if it is necessary to replace a servo motor or the blend door? I'm trying to determine if the cost savings is really worth the trouble since it has been said that this is quite a pain to replace. I didn't find any other posts with details of the process.

I am not in any particular hurry to get this repaired since it is approaching summer, but my wife will not be happy if she has no heat come fall. I would like to get as much info as possible before attempting to go into the dash myself.

BTW, has anyone paid to have this fixed? What cost might I expect if I take it to a Lexus or Toyota dealer?

[chilkoot]

aside from the cable problem how did the replacement of the valve itself go? Was it fairly straightforward? I've got a replacement sitting in my trunk waiting to be installed, but haven't read much about it yet.

[BogeyJH]

aside from the cable problem how did the replacement of the valve itself go? Was it fairly straightforward? I've got a replacement sitting in my trunk waiting to be installed, but haven't read much about it yet.

The clamp on the hose that connects to the bottom of the HCV appeared to me to be unserviceable. I've never seen this type of clamp. It included a cotter pin which I could not remove. I ended up cutting the clamp off and put a new worm gear band clamp in its place.

There will be a little loss of coolant, but not enough to worry about draining it beforehand. All in all, a pretty straightforward process. Good luck!