Bypassing IHKR/F3 for rear defrost...

[Montreal525]

My CCM seems to be on the fritz... Defrost, a/c and recirc. work when they want too. All fuses, relays and switches check out so It has to be the CCM.

Now, my heater valve is stuck as of 2 weeks ago. I don't mind for now as winter is coming. Heater works fine and blows hot and I still get some measure of control by playing with the hot/cold knob in between the upper dash vents. Controls for where it blows (windshield, dash, feet) are fine.

The rear defrost is another problem. I need it. As anyone bypassed the CCM control and rigged it either with a separate switch or that it works permantely?

On the picture, by removing the relay and jumping the connections in the C box, defrost should work all the time. But that's another problem, all the time would mean even when the car is off since the off switch should be provided by the connection in the A box, to the starting / charching system. I was thinking of putting a switch in between the connections in the C box, with an extra fuse as protection, to control it and a mental note not to forget it.

Another option, more complicated, would be to loop the connection in the B box that goes out to the CCM to somewhere else to fool the relay in thinking it's got the signal to operate. I'm not even sure if it's possible.

Any thoughts or comments?

Is it possible or am I dreaming?

Am I way off in my understanding of the system?

Should I start thinking about a bus pass?

BTW, I am looking another IHKR/F3, if I can make it thru winter, it would be a major plus...

Jeff