Intellitec electronic climate control management thermostat

[vagabond317]

My 1997 Fleetwood 37' PAV has 2 a/c units and 2 furnaces all controlled by the intellitec electronic climate control thermostat (00-00597-000) in combination with the ecc energy management unit master controller (00-00591-100). Everything works fine except my rear furnace which does not come on at all. I have eliminated it down to either the thermostat or the master control unit. But how do I figure out which is the problem?
I understand that there is a relay inside the master controller that has to close when energized for the furnace to turn on. When I unplug the pc4 plug and jumper pins 4 and 5, the furnace starts, no problem. So for some reason, that relay inside the controller is not closing. How do I tell if it is because the relay is bad or if the thermostat is not sending the signal? The only wires coming out of the thermostat are a brown one and a yellow one (it also has the two thermistors coming into it). How does it signal to the controller what unit I am trying to turn on? And finally, if it is the controller, is it possible to take it apart and just replace the internal relay? According to the troubleshooting guide in the service manual, when you move the temperature setting up and down, you should hear a click from the controller relay at some point along the scale. I do hear the click. It says if you don't hear a click, replace the controller. But I do hear a click, so I go to the next step which says to jumper the pc4 plug. That does make my furnace start. But the guide doesn't tell me what that means. It only says that if t doesn't start, check for loose wiring. Can anyone please help?

[shastagary]

you might try emailing intellitec and see if they have suggestions. Intellitec Products LLC technical helpline Mark or Chris Bayus 419 965 3014 or email mmrvelectronics@yahoo.com (from there website)

[vagabond317]

Thanks for the repair info. I will check into that. The service manual is immensely helpful, so I highly recommend anyone else with problems to download it. But I already have it which is how I got this far. But thank you for your help!

[vagabond317]

I do have the wiring diagrams and service manual. But there are only two solid copper wires going from the stat to the controller. One is brown and is the ground and the other is yellow and is the signal wire. So I can't change the input into the controller. I did try swapping thermistors to see if it was a bad temp sensor going into the stat. But the front furnace worked with either thermistor and the rear worked with neither. I could swap the output around, but that wouldn't tell me anything new. How do you test the signal wire? Should it send different voltage based on which unit should kick on?

[shastagary]

here is some info that should help SERVICE MANUAL and a repair place This module is repairable

[MrWizard]

Do you have the wiring diagram and manual for the control
Turn off all power including battery

Swap the power control wires for the the two heaters
Put rear on front, from on rear, aka swap zones

Now rear stat controls front heater, front controls rear

Turn up the front stat, does the rear heater come on?

Turn up rear stat does front heater come on

The results will tell you whether it's the stat, the control, or the heater