[KRD]

Sorry, was not sure where to put this. In my 77 Trans am, when I have been driving for awhile in stop and go traffic it seems as if the heater is on. (It seems to be on all the time just more noticeable in the traffic) All the controls are off but it blows really hot air. During the summers here in Arizona that can be horrible. My legs have gotton welts on them form the heat. Any ideas?

[Fast Orange]

I'm not familiar with your heating system,but I would start by checking the heater control valve and any vacuum lines or cable controls for it.Your car may not even have a HCV,but youcould put one in the heater hoses to stop any coolant flow into the passenger compartment.
Another possible problem may be the vacuum lines that control the "blend doors" in the heater itself.

George

[docvette]

Doc here,

Another Common failure in the General Misery Heater switch is the "Off/Low speed" configuration..

What is marked as "Off" is actually running at low speed on the fan motor when the switch fails..and may be pushing hot air past the vent doors..

With the heater/AC in the off position, turn the key to "ON" in a quiet spot, does the heater motor wind up? If so, get a new switch...until then you can just pull the heater fan fuse..which will ease any body Dehydration issue you may have

If with that off you still feel heat, then you might want to check the doors as Fast Orange recommends ... one or more may be stuck open.

Doc

[KRD]

thanks I will check it as soon as I can.

[OneMoreTime]

I have had some old trucks that had those kinds of issues so I put a valve in the heater hose and shut the water off completely in the summer..in the winter just truned that valve to the on position..

This may work for you until you can find all the pieces to fix it like the factory intended..

OMT

[KRD]

just went and checked it. It sound like the fan comes on with the ingnition. So I will have to get a new switch and try it. For now untill then I'm going to put a valve in it. Thanks

[docvette]

Originally Posted by KRD

just went and checked it. It sound like the fan comes on with the ingnition. So I will have to get a new switch and try it. For now untill then I'm going to put a valve in it. Thanks

Doc here,

The Valve that OMT mentioned works Great (even with a properly operating Switch!) I use them on All the Corvettes (which are Factory uninsulated, and hot as chili Pepper inside!)

During the summer, The interior of the Vettes can go as high as 120 degrees from Engine and firewall heat, and using the valves to cut the flow of water inside the cabin help a lot...

I use Stainless Steel Ball valves, they are more expensive, but don't rust, block, or leak...and look good in the engine compartment..I use them on BOTH the inlet and outlet hoses..

Someday I will break down and buy a fire blanket for the floorboards and firewall, but until then I'd rather invest in parts that make and keep them going fast...

Doc