Ruud ac wont come on. mfg 03/99. thermostat

If you turn your T.Stat to run and it comes on but in the auto mode it does not come on and the condensed compressor and ODF COMES ON sounds like you need a circuit board

An open limit switch may make the fan run all the time. Try disconnecting the Green wire @ the furnace...if that does the trick, then either the thermostat fan relay is stuck, or there is a short between the Red & Green wires somewhere in the thermostat wire.

Have them turn the outdoor unit off and wait a few minutes. When they turn it back on they should here
the fan and the compressor come on. They are to different sounds.

If they think that they have both come on, tell them to check the black insulated suction line. it should at least cold to the touch. If not it could be a freon issue.

If the line does get cold, have them checkthe filter in the house. If that is ok tell them to turn the power off
to the outside unit. Take a garden hose and wash
the outside coils on the outdoor unit,be carefull not to
smash the fins. Wash them at an angle from top to bottom.

sounds like u have the thermostat wired wrong or bad wires i would check that first make sure you have the wright thermostat

the A coil is froze up the low pressure side is too low, add freon

In many mobile homes this scenario is very common, less so in permanent homes, but here is how it works; The heat side of your fan which is the low fan speed is not dependant on the thermostat it's heat activated. Your already aware of this to some degree because you had the limit \fan switch replaced. I've taken that approach to that unit myself. In reality what probably is happening is on hot days your unit is warming up by being hit by sunshine and then it clicks the fan on at 140 degrees. This especially happens if the unit is on the roof or a split system in the attic. Remedies; run your A\C to cool it down, keep your attic cooler by way of an attic exhaust fan(which saves you cash anyway). Or if your not regularly using A\C turn breaker off til you need it. In the end there may be something going on, but odds are I'm dead on. Good Luck

Is the outside unit running? Fan and compressor?

Could be a faulty thermostat, (referring to the furnace\heater. As far as the A.C., you must have a dual thermostat with a switch for A.C. and Heating. Is the thermostat digital or mercury bulb? As for the A.C. it sounds like it is going off on high discharge pressure. Is the cooling fan running that cools the condenser? It must be spinning freely or it may be starting and because it is partially seized, it will cut off with a high current draw. Anyways, the condenser must be clear of any debris, no shrubs around it. The compressor could be bad and trying to start but goes off on overload because it isn't starting. It's start capacitor could be bad and not giving it that extra boost on start up which is what a start capacitor does. Good luck.

Check your thermostat in the house and make sure you have the fan switch selected to AUTO mode and NOT the ON mode..

is this a whole house air conditioner ,
if so check the fuse panel,
check to see if the outside unit runs at all , compressor or fan.
check the ac transformer power to the thermostat
check the switch in the ac closet
doe the internal fan run if you switch to fan only.