Originally Posted by
Swampotter
Ok fellas, I feel like the princess at a school prom. Love all the ideas so keep them coming. Here's today's efforts before I shut it down for Holidays.
1) it's currently 61 outside. I fired up the car and the temps from all vents at the coldest setting (no a/c) is blowing 53 degrees (I'm assuming it's because the antifreeze is colder because of overnight temps). Hoses at the firewall are cold, valves are cold, hose feeding valve is cold.
2) bringing car to temp. After 5 minutes of idle, hoses are all cold, temp in cabin is 58 degrees. The valves are warm. 80 degrees according to my laser gauge. (I find this odd)
3) 15 minutes in, interior temps now 58, surface temp of the valves are 104, hose feeding the valve is 63 and the hoses at the firewall are 62.
4) drives side heat now full blast, 115 and climbing in the cabin, passenger 80 and climbing. Drivers valve 125, passenger 113. Feeder hose 130, drives hose at firewall 130, passenger 85.
5) both sides full heat. 130 out both vents, both valves about 130 as well.
6) all settings at coldest (no a/c) and waited 10 minutes at full blast. Cabin air is coming out at 70, the drives side valve is a blistering 150 and the passenger valve is 125.
I didn't hear any opening and closing of valves with the engine running though I can feel antifreeze flowing thru the feeder hose. The valves do cycle with the engine off but not rhythmically.
As it sits, it looks like the valves are operating normally (good thing it worked correctly during these tests), as having it malfunction skewers test results. Remember, the valves are powered on when closed (max cool dials), so the valve tops will warm up since the coils are energized/heating up (your reference to them being @ 80 degrees, and being odd). The key note is, both hoses are cool and the cabin is cool. If you were to again throttle the dials, then the hoses (respective to the zone adjusted) will heat up. Also, remember you noted the valve tops were at 130 along with the hoses, all that means is the heat from the coolant made everything hot after flowing through the lines during the heat selections. Remember also, you would not have heard the valves open/close, you can just 'feel' the tops of the valves as they cycle. An example of this would be set the dials to mid level, while the car/system hot & running, just lightly 'cup' one, or both valve caps. If you use your free hand, you can also 'feel' the coolant lines as the valves 'surge' when those duovalves cycle. At this stage, your valves seem to be working correctly. This is the case where this intermittent problem gets harder. Did you find that .pdf for the control head fix a member discovered? I was experiencing this type of intermittent problem, but it has been quite a long time since it came back, so I did not do the fix that was offered.
Found it (Thanks to Dave/180 listing all these). Since I could not find it, I downloaded it again. It is attached, and references the member CL770(?). One reason I could not find it (maybe) was the listing as 'Heater/AC Speed Control Repair'. Given the number of pins, and the systemic problems with these heads, I think this 'fix' would correct this specific problem (and most of the) annoying intermittent A/C problems. Good luck with the fix, if you do it. Post back your findings/results? Hope your Christmas is fun, safe, and happy for all!