it's been awhile since I posted so please don't flame. Just bought a sc300 97. Anyone know if this part is suppose to be hooked up? Not sure what that module is called. If anyone can take a picture or assist me with how it's hook up. I would be great fully thankful.

 

Heater control valve. Should be hooked up only if you care if it gets really hot or really cold in the cabin.

I am not sure what is going on with this from your previous owner, it looks like they bypassed the vsv and put vacuum directly to the valve. I can't remember if vacuum opens or closes the valve but like it is it is one way or the other. Something must not be telling the vsv to do its thing to modulate the temp or it wouldn't have been bypassed like this.

 

hmmmm. when I turn the heater on it's hot. But when I turn it to cold it's warm. With AC on its kind warm AC. Maybe someone can take a took at theirs or show me what lines goes to what. Lol. Thanks!

 

Break the line from vacuum source at splice closest to the valve, hook it (vacuum) up to bare lower connection on vsv. Connect 2 short hoses at splice which would connect the upper vsv connection to the valve. Let us know if it all works.

 

thanks! I'll try it tomorrow! You my friend are very helpful also nice collects of SC's in your sig. lol

 

First thing is fixing up the VSV routing like RX discussed. But your symptoms sound very similar to what I dealt with:

https://www.clublexus.com/forums/per...rol-valve.html

 

So after switching the lines around. It seems to be cooler. Worst case is switch out the hcv. Thank you all!

 

Okay guys. I'm guessing I have a bad HCV because after re routing the hoses yesterday. This morning while warming up my car in 44 degree weather, I wasn't getting heat from my vents. It was straight cold lol. Before the rerouting like the picture above. I was getting heat. I guess that's why the last owner had it routed like that. Lol. Now to buy a new HCV.

 

Usually when they fail people will bypass it like the picture of yours shows so they won't freeze in the winter. Then when summer comes around they hook it up how its supposed to be.

When its hooked up like its supposed to going through the valve, if the valve is bad you won't get heat, its a common issue and you likely just have a bad vsv (vacuum switching valve).

 

thanks for the info Ali.