Coleman Blows 3amp fuse when on Cool only

[suzib6sw]

The outside unit is a Coleman/York BRHQ0421CD with a Eb17 Furnace inside.
The Inside Thermostat and Board in the outside unit have been replaced for like , new units.
There are no apparent shorts in the cables,
Then the thermostat is on heat or fan only, there is no problem.
Turn the Stat to Cool and the 3 amp fuse blows almost instantly.
By a process of elimination I have unplugged everything off the control board to see when it blows and it seems to be the Reverser valve solenoid. Connect everything and leave this unplugged and everything seems fine.. I have metered the solenoid but its not short..low resistance maybe ... If I connect a 12V battery to the solenoid, I can hear it click in and out.
Am trying to find the part number for just the solenoid as I cant replace the whole valve assembly.
Thermostat is a Honeywell Heat Pump only type with all the colored. I do have a 4 wire stat that I tried . no fuse blew but no cool, only heat in either heat or AC mode.

any further diagnostic ideas or thoughts would be greatly appreciated.. Its getting tad warm and humid

Pete

[Bill]

Hi Pete,
I am not convinced that the reversing valve this the problem. For starters it takes 24 volts to run the valve so putting 12 volts to it wont give you the correct reading. Also by putting on a 4 wire t-stat that wont run the heat pump in a/c mode. But if you are sure that it is your reversing valve you have to replace the whole valve not just the electrical part of it. That has to be done be a professional due to the fact that you have to work with freon. Also check the low volt wires that are out side by the heat pump and look for any cracks in the wire. That could blow your fuse too. Hope this helps
Bill