heater control valve location?

[Blue Steel]

i've read all the threads on climate control systems going bad, and i've come to the conclusion that the heater control valve is messed up since the max ac won't even blow cool air. only hot all the way around. i get under my car and look for the heater control valve like another thread said, and can't find the darn thing! help!!! can anyone give me specific instructions to where this could be in the sohc engine compartment for a 97? i'm completely lost. thanks in advance.

 

[Alec]

It's on top. To the left of the motor towards the firewall.

 

[KPT]

If its bad it will leak coolant out the bottom when the truck is running. Happened to both my explorer and my dad's.

 

[BradE.]

I doubt the heater control valve is the souce of your A/C problems. Typically, they cause a coolant leak as said above, not A/C trouble.

If you A/C is not blowing cold, I'd start with checking the amount of R134a in the system, you might need a recharge. Or you could have a bad blend door or blend door actuator.

 

[Blue Steel]

the freon (or whatever they put in now) was just filled two months ago, and no leaks were found. doesn't the blend door allow cold air to go through when the max a/c setting is used? please correct me if i'm wrong. also, what does the blend door actuator do? is it the motor that makes the blend door move? i'm not a afficianado when it comes to things like this. thanks for the quick responses!

 

[BradE.]

Just because the R134a was put in, and there are no leaks, does not mean that is not the problem. Overcharging can cause the symptoms you describe. You need a set of manifold gauges to check the pressure of the charge. Does the A/C compressor engage? You will hear a clicking if it does. If it clicks ever few seconds, your low on R134a.

Typically, the blend door will allow some cool air on Max A/C. The actuator is the little thing that pushes the blend door. Usually before the door dies you will hear a thud noise when moving the temp controler knob.

I suspect your problem is related with the A/C system itself, and not a heater control valve. A bad heater control valve would make the A/C discharge warmer, but not warm. You would still have relatively cool air. In addition, failure symptoms of a heater control valve typically are not hot A/C discharge. They are a coolant leak near the front right tire.

I'd start checking your A/C system, something isn't working properly.

 

[Blue Steel]

well i replaced the heater control valve and that definately helped, (the old was was sealed shut) but i was looking at the engine when the ac was running, and i noticed something... the ac pulley was not engaging at all. does this mean new compressor time? how can i make the compressor pulley engage manually? thanks so much for the help. oh and let me tell you... that little heater control valve is a bizzznitch to take out on the sohc. went through the right tire well. reminded me of replacing the spark plugs. sorry, had to gripe.

 

[Alec]

It is normal for the AC compressor to not always be engaged even when the AC is on. If the AC was working hard, however, and it didn't go on for about 5 minutes or so, the pulley clutch is bad. I think on our compressors that may mean an entire new unit.