Greetings all.

Yes, I have read available info on the forum regarding this common problem. Not to do so would invite reprimand as being a dumb a** newbie. In fact, the cooling/heating system schematics and posted advice have been immensely helpful. It has enabled me to develop a troubleshooting checklist. I'm posting as a new topic because the others are older and may not fall into the view of forum members.

So, here's what I've done...

1. Check for blocked heater core and/or blocked back flow check valves. Back flushed/"forward" flushed the heater core. All is well. Removed and checked back flow check valves, no problem. NO heat.

2. Removed aux. water pump, and determined it was shot, to the point of not even bothering to replace brushes. Purchased and installed functioning used pump. NO heat.

3. What should be next? I am aware that the water valve itself (heart of the octopus) could be the next culprit in my troubleshooting line. I had that out and apart during these festivities, with no apparent crud/blockage. I do know that the valve is electronically controlled, but am not certain of it's EXACT function aside from redirecting coolant flow, and whether that would be causing the problem. (No, I did not bench test it at the time, all scorn welcome and deserved.)

4. Last would be the CCM, but my understanding is that that module relates more to A/C function. The A/C works fine in either manual or auto mode. Maybe I'm getting chilled "heat" as a result of a faulty CCM, lol.

AFAIK, this is the extent of the troubleshooting list regarding a lack of heat.

Any advice from the residents of this forum are welcome.

Best regards,

Clay

 

If the pump is running:
-turn the heater to "hi"
-check the heater hoses. One must be hot and another one much colder
If both are cold - replace a valve
If both are exactly hot - replace a heater core
If one is hot and another one is colder - replace a temp flap motor or the flap itself.

 

Moscow, thanks for the response.

The temp flap motor issue is new to me. Is it a separate part, and if so, what location?

I understand that the inflow (to the heater core) should be hot, and less so when exiting, but not necessarily "cold". I don't understand how both hoses being hot would indicate needing a new heater core. It's just a simple exchanger, like a small "radiator". Hot in both hoses would indicate flow through the core. Is this the reference you make to the heat flap not functioning properly?

Clay