I am trying to change a faulty thermostat and the old one had a red wire connected to terminal rh with a jumper to rc, and a white wire connected to w with a jumper to y. The new thermostat I bought (cheap replacement) only has terminals w r g y. Will this thermostat work? I have tried hooking wires only to w & r, and also to w & r with jumper between w & y. The unit is in a mobile home with electric heat with central air unit. Thanks

You would need to tell us the brand and model of the stat you bought. Not all stats will work properly with electric heat. Thermostat wiring colors and furnace terminal designations repair. (http://toad.net/~jsmeenen/wiring.html)

It's a honeywell ct31 bought at wal-mart, I don't know if its compatible or not and I'm a little confused as to how only 2 wires can control 2 units. I'm sure there has to be a relay somewhere, the only thermostats I ever changed usually had 4 wires.

Here is what one of the elctricians had to say about the ct 31. https://www.askmehelpdesk.com/heating-air-conditioning/thermostat-wiring-27154.html

The unit is in a mobile home with electric heat with central air unit. thanks

Does your unit have a switch on the furnace that says heat off cool or something like that.

I haven't looked at the furnace yet, I ran out of time last night. The thermostat does have the "heat off cool" switch. I will inspect wiring on the furnace this afternoon when I get home.

Ok I guess you can tell I'm not a heat/air guy. The furnace did have the switch for heat,off,air. It was just a simple 2 wire thermostat contact for on & off. Thanks for your help.

Well, the W to Y is right
The Rc/Rh connects to R on the new stat.

The reason why W & Y are connected together is that the mode is selected at the furnace.

You have to select it at the stat too.

An Autochangeover stat would enable you to not having to select it at the stat, but you would still have to select it at the furnace to change the mode.

Some mobile home furnaces toss a regular HVAC guy problem also because of the heat/off/AC switch and the accociated relays contained in the control box.