Need help identifying transformer wires
You should first identify the windings. It's likely that wires on each side form a winding, so blue and orange might be a winding, and white and yellow form another winding. Look for pairs of wires that read low resistence between them.

Once you find the pairs (or windings), do the next check: cross check each winding to be sure the transformer is not shorted. In other words: measure resistence between wires of different windings. If resistence is in the order of M&Omega;, transformer is good. Lower resistence (in the order of k&Omega;) may indicate a short between windings.

Now note the resistence of each winding. One should read considerably higher than the other. For example: one winding measures a few ohms, the other one a few hundred ohms. The higher resistence winding will work with higher voltage and less current. The lower resistence one will work at lower voltage and higher current.

At this point, you already know what you asked: to identify the wires/windings. Now you can optionally test the voltage ratio of your transformer, if you have an AC power source: get a resistor between 10k&Omega; and 100k&Omega; and connect it to the lower resistence winding, and apply a 5V, 60Hz AC (preferably sinusoidal) voltage to the higher resistence winding. Then, measure voltage across the resistor. You should read a voltage lower than 5V. The ratio between this voltage and 5V will give you the voltage conversion rate of your transformer.

The values I suggested (5V, 10k&Omega; / 100k&Omega;) are quite conservative, and are not likely to cause accidents, sparks or anything. Just be sure it's an AC voltage about 60Hz, not DC!