Rear Heater (6 Viewers)

[96GreatWhite]

Hi all. 96 Land Cruiser question. After driving for a few minutes, heat begins to come from under the passenger (right side) seat. I took the seat out and tested the rear heater fan as well as the fan switch on the dash- both are working perfectly. Water is flowing into the little heater core under the seat at all times. My question - should water be flowing into that heater core all the time or is something (water valve?) not working properly? I can buy the bypass kit from LCP, but would rather have the option of using the rear heat when needed.

BTW - The AC is ice cold and the under dash damper is working fine as well.

Thank you! Ron

 

[Kernal]

Is your hot water (heater) system stock ie: has anyone modified the hose configuration/flow of water?

Does the heat coming out of the main heater change when you adjust the HVAC control slider (AC off).

First check the heat control valve on the firewall just behind and above the valve cover. There is a short lever that when turned opens and closes the flow of hot water to the heater cores. There should be a small cable attached to that lever, is it still attached? Does the lever move when you move the slider (ignition ON or engine running) of the HVAC controls?

Might help to take a photo or two of the heat control valve and the hoses/pipes in that area (from a few feet away) and post them up.

 

[96GreatWhite]

Thank you Kernal. I believe the system is as designed. All of the heater hoses were replaced recently as a part of normal maintenance that I do. The problem existed before that as well though. The cable is connected to the water valve and it is moving up and down as you change the temperature setting on the dash. When on cold, the lever is in the UP position and when on warm, the lever moves down towards the motor.
General view

:

Temperature lever on cool below: - lever is in 'UP' position

Temperature lever on warm below - lever has moved towards the motor/firewall:

 

[Kernal]

One thing you can try is (Key ON or engine running), first slide the HVAC control lever to FULL Cold (no heat), then slide the cable eyelet off the heat control valve lever. Then manually turn the lever to the closed position and notice how far the lever moved ie: if it moves a lot then the cable position needs to be adjusted.

If you don't need heat in the cabin you can leave the cable disconnected from the Heat Control Valve (HCV) then manually push the lever
to the closed position and it should stay there, IME.

 

[BILT4ME]

Also, depending on the brand of heater valve you have, some of them do not close all the way.

I have had one from RockAuto that couldn't close 100%.

Also, there has been at least one person on here that installed the wrong year heater valve and the actuation was backwards from what it was supposed to be. The culprit was a 93+ truck that someone installed one from a 91-92 and it apparently operates the opposite direction.

The rear heater should NOT have heat coming out of it if the slider is all the way cold. As @Kernal stated, cable adjustment and make sure the valve is moving freely.

 

[96GreatWhite]

Thanks all! I will take the seat back out and do a little investigation. Hopefully just an adjustment needed.

 

[Kernal]

@96GreatWhite : You don't need to remove the passenger seat to adjust the heat control valve or it's cable. The cable does not run from the heater core to the heat control valve, it runs from the heat control valve on the firewall to the HVAC assembly behind the dash, but you adjust the cable at the valve.

 

[96GreatWhite]

I pulled the cable off of the valve lever and the lever is not closing all the way up. So I need to adjust the cable. There is a small clip underneath the cable that appears to be holding it in place. Do I just remove it and adjust the cable out or is there something else? Thanks!!!

 

[BILT4ME]

Thanks all! I will take the seat back out and do a little investigation. Hopefully just an adjustment needed.

The valve we're talking about is on the firewall, not under the seat......

 

[96GreatWhite]

Yes, I am asking about how to adjust the cable running from the temp slider on the control panel to the water valve directly above the rear of the engine on the firewall. I pulled the little clip off that holds the cable, but the sheathing doesn't want to move easily. Don't want to break anything. Cable is detached per picture and I need to pull it out a little more. Just making sure there is not something holding the other end of the cable down or something else that I need to disconnect. The cable itself moves freely in the sheathing, and it is fully extended in the picture.

 

[96GreatWhite]

I was able to pull the sheathing out of the firewall grommet about a half an inch or so and reseat the spring clamp. Now the valve is traveling all the way to the stop. Test drive this evening. Thanks to all for your help.