No display on Dometic 5 button system

[grapepickers]

My 04 Newmar Kountry Star 5th wheel with Dometic 59516.331 AC and Suburban SF3.5 furnace:

1. 13.35VDC on red and black lines of wires behind CCC
2. Replaced 3109228.001 Comfort Control 2x with new units-no display
3. Replaced R11 connector behind controller per Dometic advise
4. Reset units by holding MODE and ZONE buttons while turning on switch
5. Have 13.35 VDC on circuit board solder points

Still nothing on display! What's wrong?
Thanks,
Bruce
Blong321@roadrunner.com

[dougrainer]

grapepickers wrote:
Thanks for the info, Doug. The 13.35 volts is from the 4 conductor flat communication cable behind wall stat. I have one AC. Took off shroud on top and opened the box. I suppose this is the control box? About 6"x10"x2" with an access panel about 3"x4". Took the whole cover off and could not see any obvious burns or poor contacts. The 8 dip switches have #5 for furnace turned on, the others are off. Paperwork on box is too bad to read. Am I looking at the control box? Thank You, Bruce

Yes, you are looking at the control box. What does the Telephone cable ends look like at the control box? Odds are your telephone type cable is cut between the Control box and the wall tstat. Doug

[diveman52]

You might try replacing the RJ12 connector at the control panel in the AC unit. If you have two AC units or AC/Heat pumps there also a telephone cable running between the to units.

[grapepickers]

Thanks for the info, Doug. The 13.35 volts is from the 4 conductor flat communication cable behind wall stat. I have one AC. Took off shroud on top and opened the box. I suppose this is the control box? About 6"x10"x2" with an access panel about 3"x4". Took the whole cover off and could not see any obvious burns or poor contacts. The 8 dip switches have #5 for furnace turned on, the others are off. Paperwork on box is too bad to read. Am I looking at the control box? Thank You, Bruce

[dougrainer]

The CCC stands for the wall tstat. There should be NO wires at all except a 4 wire telephone communication cable. If you call the roof top control box the CCC, then yes, you will have a 12 volt pos and a 12 volt neg at that box. If you have NO display, then a reset is futile. You must have a display for a reset to happen. The wall CCC RARELY ever fails. What does fail is the roof top Control board. Have you replaced any of the roof top AC units recently? How many Roof top units do you have? Your model AC unit has the control box separate and mounted on the Evap cover. Doug