06 Relay Heater not working - symptom list

[Los Dos Dave]

Hello gurus,
Hoping for some advice on where to look first to get the heater working in my 2006 Relay. Here are the symptoms that have been observed related to the heater as well as the AC, in no particular order.

* Last winter, when temp control on the dash was set in the red, the air blown into the cab was cold, but the engine temperature gauge would rise rapidly to the overheat range. This would happen whether in defrost or normal heat mode, sitting-still or in-motion. It had been working at the start of the winter and suddenly started this behavior. This winter, we are not seeing the engine over-heat phenomenon.
* The AC fan blows weakly... that is the AC compressor is making cold air but the blower barely pushes it into the cab.
* Once in a while a loud rapid oscillating clicking will occur inside the dash when the mode switch is moved to Normal, and will stop when moved to Max mode.

I realize that I may have three or more issues that I need to tackle, but I don't think my wife is going to tolerate going the rest of the winter with no heat. I suppose that I could have a bad heater-control valve, but don't want to go searching for it and replace it if it sounds like it is more likely to be something else.

Thanks for any recommendations on any of the above listed problems.
dave

[fdryer]

A subscription to alldata will give full access to service manuals for anyone intending to service and maintain their own vehicles. You will find more info compared to shared experiences on public message boards. If anything, the forums complement service manuals.

One of the first things to ask about heating and cooling - was the cooling system ever flushed and replaced with new antifreeze? If there's a cabin air filter, was this ever replaced periodically? I'm not 100% familiar with Relays but Saturn doesn't use a coolant shut off valve in most of the model line simply to eliminate a potential problem. In effect, the cooling system is continually circulating and the only requirements are to ensure fluid level in the coolant container is topped off and periodic coolant flushing done. Dexcool was the first antifreeze made for 5 years or 100k miles before requiring replacement and is recommended to ensure long term reliability of the water pump and reduce clogging.