I don’t know why but I can’t get them to work, I checked the fuse and every thing and it’s all fine I think it may be the dimmer switch but I’m not sure if anyone has the factory service manual and could look up how to check it, or have any other ideas or suggestion I could use all the help I can get. Thanks 
if the fuses are ok. so u got no light on the dashboard? or the dimmer switch just dont work and u got light? try checking the bulbs back there or the wireing.
checked bulbs there fine and wireing all looks fine
From my 91 etm there are two fuses:
1 under hood fuse #33 50amp if this is blown your headlights wouldn’t work
2 dash fuse box #11 15amp this supplies power to all dash bulbs and dimmer switch. this fuse is fed from red/grn at headlight switch.
The dimmer has three wires:
red/blk-12v power in
red- to ground side of all bulbs
blk- ground
since all bulbs don’t work check for
1 12v at dimmer red/blk
2 ground at dimmer blk
3 replace dimmer