1992 Dodge Colt

The blower fan will not turn on.I have taken out motor works well.I have over 12volts on blower wires lites test lite but will not start fan.I put a resistor and fan in out of a geo metro wiring all the same but still did not work. The fan does not work on high. What should I do next.
January 21, 2011.

Check the ground. Also, make sure when you put it on high with a draw on the it, the switch doesn't give out.