Why don't my low beam headlight's come on?

I replaced my combination switch on my car because my high speed for my windshield wipers wasn't operating properly.When I say it wasn't operating properly I mean it was moving at a slower than normal speed.All the other functions on the switch operated properly.
The new switch (salvage yard) which had solved my wiper problem left me with my high beam lights working only, no low beams.Is the dimmer switch on the combo switch causing me only to have high beam lights? Should I get another combo switch?
The bulbs and fuses look ok.