A sunbeam blanket only reaches a medium high temp, heats up for 1 min. and shuts off, the blanket is rated at 180 watts and 1.5 amps but when tested is drawing 90 watts and .8 amps.

Sounds like the heating elements are shorted and only allowing a smaller portion to operate.

Discard the blanket.

Just curious, but how are you making these measurements?

Watts is a measurement of heat loss, in this case the heat generated by the heating element.

Mathematically speaking, the voltage is correct for first wattage. 180(W) / 1.5 (A) = 120 (V). That would be correct for for the United States and Canada. The resistance of the circuit would be 120 (V) / 1.5 (A) = 80 (O).

However, the calculations for your second value are way off. 90 (W) / 0.8 (A) = 1125 (V) so the resistance of the blanket would be 1125 (V) / 0.8 (A) = 1,406 (O).

Either your measurements are incorrect or most of the blanket's elements are fried open.

But again I question your measurements and the statement, "draws watts". Again amperage is drawn, wattage is the heat output.

If you get rid of it, I hope you get a heated mattress pad instead - a very few watts, better for you, and heating you instead of the room.

1/2 of the heating elements are gone.