Also should note-

The clicking in the CCU only occurs when the car is warmed up to operating temperatures. It gets worse as the car warms up....

Does this happen to you @ivandrocco?

What year is your car?
 

Re: clicking.....try unplugging the aux. water pump. It may be having problems and tripping CCU circuit protection.

UPDATE: PROBLEM SOLVED!

Poking around the engine bay I found the thermo switch by the egr broken in the plug, sending an intermittent signal to the CCU, thus creating the clicking. For now its unplugged, no clicking and full heat. Will replace as soon as possible.

Hope this helps-

Can you send a photo? not sure what switch you're talking about. You mean the aux pump connector?

Popped new innards in the monovalve... and now my heat is cold all the time instead of just lukewarm. Thanks obama!

I'll try it. I checked this out the other day and the plug is very corroded, was planning on trying to clean it up.

http://www.peachparts.com/shopforum/...03-medium-.jpg

It is this Thermo switch (the red capped one in this picture, by the EGR that was causing my CCU to click repeatedly. Once the new one comes I assume everything will be back to normal, will update when installed

nice block off plate

nice clean motor too

unplugged the aforementioned plug, no difference. cold air on all settings.

But did you test the plug with an ohm meter? the wiring? the pump its connected too? the pump its connected to is triggered by this switch, no switch no full heat. I've been able to get lukewarm heat when switch is unplugged, but you have to troubleshoot these issues further than an unplug or not.

red switch unplugged - heat with key in on position, no heat with car running

aux pump unplugged - heat with engine running, no heat at highway speed

I believe that connector you unplugged on the thermostat housing is for controlling the blower fan so it does not blow cold air when the engine is cold.

Can you feel all the coolant hoses by the firewall ( from a cold start), starting from the hose coming out of the cylinder head by the oil filter and report back with your results? Make a video of it if you can. If the temp wheel is set to max, the hose coming out of the cylinder head should get warm first within a few minutes, the other hoses in and out of the firewall should follow, then hose to the mono valve to the aux pump back to the engine.

seems like this is what is happening. i now have heat at idle with a new monovalve diaphragm the aux pump unplugged, but heat goes cold at highway speeds.

Still dealing with this issue. I think a flap is the culprit, allowing cold air in that overwhelms the heat at high speeds. Winter is coming! help!