Lexus1994

I just purchased a 1994 LS400 with the heater not working. The air blows, but no hot air. Help would be very much appreciated. Thanks for your time.

I do not have owners manuel so I'm having to guess where everything is at the moment.

AzHotLS

iTrader: (1)

Welcome to the forum.

The first thing I would check is the heater valve under the hood, see post 5 in this thread:

https://www.clublexus.com/forums/ls4...r-problem.html

tmahan

I had the same problem.

Run the car and turn the AC to max. Kil the engin and look at the heater control valve under the hood on the firewall. It should be all the way down.

Get back in the car start it up and turn the heat on full. Now go look at the valve, it should be all the way up.

If not look under the dash on the drivers side near the hump in the middle and
there is a black motor about 2" square with the cable attached on the inside.

Mine was broken.

I replaced it with a piece of coat hanger and it is working great.

Lexus1994

Thank you azhot and tmahan.

That is definately part of the problem. The cable is not working. I aslo added and bled the coolant. I think that was part of the problem as well.

tmahan,
The cable is not moving. How did you get to it to replace it. I see the black box and there are some white plastic arms connected to it that move when I change the temperature. But I don't see where the cable connects.

Thanks for all you guys help.

TexFinn

Heater??? We don't need no stinkin' heaters here in TX.

Have you also checked the heater core? Maybe it is clogged, or even bypassed.

Chris2

iTrader: (2)

I'll I started at the wrong point with my heat. Checks parts and all along it was fluid. Check your fluid first then go from there. Chicago is no place to be without heat.

steve2006

The valve is operated by a cable as you know, this cable connects to a servo motor which moves as instructed by the AC ECU.
If you need heat right now disconnect the cable at the valve then manually open the valve by operating the lever by hand to the hot position.
Find the problem and fix it when the weather gets warmer.

billydpowe

iTrader: (1)

a hint to the wise should be sufficient.......

deanshark

I don't think that will work b/c that cable by moving the heater valve it also opens other doors on the heater assembly. Sometimes the cable gets a kink in it and wont opperate.
Lexus1994; The servomotor you're looking for is on the passenger side. Check out this thread, post #17, from last week. https://www.clublexus.com/forums/ls4...3-ls400-2.html