Please help me! I decided to change my programmable thermostat that had been acting weird. SO while my hubby was out I thought I would surprise him and do it myself. Well the first thing I did was take off the old one . Then got the new one out and began reading the instructions. First do not disconnect the old one with out marking which wires are which... ooops. So now I have 2 red wires and two white wires and the old thermostat which reads w y g rc r and no idea where the wires were. Can anyone help me! Oh and we have central AC as well

If you have 2 red wires, and 2 white wires with no discernible difference between the 2 like colours... then no one is going to be able to offer much help. Can you not remember at all where the other wires were on the old thermostat?

Thanks for answering so quick. No I don't know which wires were where. I have tried connecting red to rc and the other red to r white to w and white wire to g . I have tried switching the wires around and have the furnace cutting in when I have the cool switch on. Question: is it safe to be trying different combos... what do I do ? Should I call an electrician. Thanks again

Look closely. You could have red with white stripe and white with red stripes.

No I just checked. They are 2 red and 2 white. But there r five connections w y g rc and r?

I think I need to call someone LOL. Uggg

Question: can I blow the house up trying different combos. I just read something that says if u don't know do not guess.. YIKES

Let me help you, with only four wires you are safe to try different combinations. First place a piece of mastic tape on each wire, (so you can write on it) next take one red wire and touch it to each wire separately until you hear the furnace fan run, now you have found the "R " and "G" wires (but we don't know which is which), now touch one of the wires that we have identified as "R" & "G" to one of the unidentified wires if the outdoor unit comes on the unidentified wire that you touched is "Y" and the wire that you touched to it is the "R" wire, the last unidentified wire when touched by the red(R) wire should bring on the furnace gas valve and this wire is "W" (if nothing works when you touch one of the identified wires to one of the unidentified wires then this is the "G" wire and try touching the other identified wire to the unidentified wires as I have stated above.Good luck to you, Mike

Also there shoud be a jumper wire on the new thermostat between "RC" and "RH" the wires when identified will go to the terminals as marked W, G, Y, with the "R" wire connecting to the "RC,RH" with the jumper. Let me know if you have any problems with this. Mike

*sigh* I meant hazArdous.

O thank you so much . I will let you know how I make out.!

acetc , your advice and step by step instructions were perfect. Thank you so much. You saved the day for me! :)