No led display on the inside furnace i am getting high voltage outside but doesnt appear to be gettin low voltage????

It should be a 2 wire hook up. If you can obviously tell what to wires were used (meaning the rest are wrapped around) then it should be easy. Turn off unit at tstat. Turn off power to condenser. Open panel and locate likely a blue and yellow wire but regardless the color they should be the only wires that are not landed somewhere. The can be traced to the sides of the contactor. The high voltage goes to the bottom, low voltage to the sides of contactor. Wire nut your 2 "obvious" wires. If you can not tell what 2 colors were used you will have to look in furnace/air handler. TURN POWER OFF FIRST. Typically you'll have 2 sets of low voltage in the furnace. One goes to the tstat the other to the condenser. Track the wire that comes in with the copper through the wall. This is likely your wire that goes outside. Whatever 2 colors are used inside you must use outside. Good Luck!!

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your furnace uses 115 power & there is a transformer in this unit that powers the low voltage controls. i would say that when they replaced the board they missed some issues with the low voltage control wires. which is likely to be what cause the board to go bad. theses low voltage wires are the only thing that can tell the outside unit to come on. the lights dimming tells me that you have a bad capacitor or need a hard start kit. the lights normally only dim if the compressor doesnt start.

The control voltage comes straight from the furnace or thermostat. Its 2 to 5 wires depending on if you have a heat pump or conventional system. If you have a control board on the inside of the furnace that has the terminal (y), then your control voltage will come from that terminal and the common terminal. Sometimes they have it connected to the (y) terminal from the thermostat, but will usually still be hooked up inside or right by the furnace. In (COOL) mode, the thermostat energizes the y and g terminals, (cooling and fan), which is sent to the outside unit on the contactor. You need 24v going to the contactor outside for it to pull in and make contact. If you have lost the low voltage, then it usually means bad transformer on the furnace (which nothing would work), faulty control board on furnace, faulty thermostat, or your low voltage wires could of been cut, chewed through, etc. If you do have the low voltage by chance, then it could be a faulty contactor on the condensing unit. I'm just throwing some things out there, its kind of difficult without knowing all the equipment you have. Have anymore questions, just ask. Good luck!

You need to get low voltage wire known as 5 wire. run wires thru wall to stat and furnace Red wire goes to R terminal white to W terminal Green to G terminal Yellow to Y terminal on both the stat and furnace circuit board. Now you need a wire called 2 wire low voltage wire run that from furnace circuit board to outside A/C. At furnace hook red wire to Y terminal and white to C terminal doesnt matter which ones you hook up at outside unit. Do it just like i told you this will work properly.
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Sounds like you might have a low voltage short possibly at contactor at outside unit (Condenser).
What happens is if your contactor has a short it will pop a 3 or 5 amp fuse at the furnace circuit board. This fuse will continue to pop until the short is fixed the best way I have found is to take off all low voltage wiring at furnace circuit board put them back one by one first with R then W then G then Y if it pops at Y your contactor has to be replaced.

there is no fuse on your condensing unit outside. pull the disconnect to kill the power to the unit and take off the removable panel above the 2 service valves. there will be an oval shaped capacitor that is marked herm and fan. there will be a rupture disc on the top that may have ruptured. also inspect the low voltage wiring(will still be hot unless you turn off the switch at your furnace). this low voltage wire operates a magnetic coil on the bottom of the contactor that closes a high voltage circuit to the fan and compressor.

It's a 24v transformer. Your indoor unit houses the transformer for the outdoor unit. The outdoor has a low voltage (24v) supply running to it to push in the contactor for the outdoor unit to run. If your air handler inside has no power then it will kill your LOW VOLTAGE power to the outdoor unit. You will still have the high voltage power to the outdoor unit. You may have a fuse on the switch for your air handler blown if there is one. On the disconnect switch mounted to your air handler, you will have a door to open and a fuse in there. If not, check your main breaker at the panel. If you don't know what a transformer looks like, you may want to have someone familiar with electrical of HVAC help you. To check the transformer for power, you first need power to your air handler, which you don't have. I would say that is not your problem. I would assume your air conditioner is not running outside, correct? Your problem is the power (HIGH VOLTAGE) to your air handler. Loose wires, blown fuse, tripped breaker etc...

This solution is based on a non-heat pump split system (furnace inside and condensing unit outside). The relay takes 24vac to energize and pull in closing the high voltage circuit to the compressor and condenser fan. If 24vac is present at the coil (two side terminals with smaller wire) and the relay does not pull in you need a new one. If no 24v is present then the outside unit is not getting the signal from the furnace and thermostat. If you pop off the furnace covers and access the control board your wires that go outside land on terminals C and Y. Y should have two wires, one from the thermostat and and the second goes to the outside unit. Test for 24v between C and Y. You must bypass the safety switch on the door prior to testing because that switch will cut off the power to the furnace. If nothing then you have a thermostat problem. If voltage is present you have a wiring issue between the furnace and outside unit.

Look at the contactor on the condensing unit, remove the low voltage wires to the contactor and turn on the system. If the low voltage fuse doesn't blow, replace the contactor.

Check to see if there's low voltage reaching the contactor's coil. If there is. and it doesn't close (pull in), then it's defective and should be replaced. Cut the power and check ohms to be certain.