Headlights wont work on dim, only bright

I don't believe there is a fuse. There is a circuit breaker built into the headlight switch. If you are sure the headlight switch is good, it could be a bad dimmer switch. If you have a voltmeter, with the headlight switch turned on, a larger yellow wire going from the headlight switch to the dimmer switch should be a hot wire. The dimmer switch sends power on a tan wire to the low beams, and through a light green wire to the high beam bulbs.
If your high beam indicator on the dash also doesn't work, then it is likely one of those switches. A voltmeter or test light would need to be used to find which one is bad. If you can find the connector at the steering column going to the dimmer switch, pull it apart and check for power on the yellow wire coming from the headlight switch, with the headlight switch turned on. If no power, the headlight switch is bad. If there is power there, then the dimmer switch must be bad.

That is a common problem, the switch needs changing if the high and low beams do work, the only problem is that it's an expensive part to replace, try a local wrecking yard they should have a bunch of suitable replacements at a reduced price.

i had this happen with my dodge ram 1500. the guy i bought it from put 350 dollar moon lit lights in with leds and they looked impressive but the issue was that they didnt go bright and i could only see 40 feet in front of me and i was sure taping led flashlights would have done me more good that those stupid headlights. then i had the idea of if the brights work and the dims dont then that means no electricity is getting to the dims so i decided to bridge the power from the bright headlight to the dims and it made all four work. now they all work, and only on bright. so im figuring there is a issue with the wiring in the truck. so this is a temporary solution if you really need just plain old lights like i did because i live out in the country

This is very common. the headlight switch is bad. replace the switch and that should solve the problem.

i have run into some that the dash lights dont work at all or they come on and off while driving.
the switch goes bad. there is also a dimmer switch . the dimmer switch controls the dim or brightness off the lights.

you could have a dimmer switch problem that may need an adjustment or replacement.do you hear the switch click when you try to change from high to low,if not than these could be the problem.the switch is located on the top of the steering colume and the base of the colume under the dash.if you work the dimmer switch on the colume and put your hand on the colume under the dash you should be able to feel the rod that pushes on the switch.follow the rod down and it will go to the dimmer switch.there are 2 5/16 bolts that hold it in place that if you loosen them and push the switch up towards the steering wheel it will move it so the rod won`t have to move as far to change from low to high.if this is not the problem and you don`t hear a click then its usually a switch replacement.

The dimmer switch is located in the turn signal lever. Simply pull it back or push forward to turn on the brights.

either the turn signal arm or a foot switch at the driver left foot area---pull the turn signal arm towards the driver to see if it clicks the headlights bright or dim-----if not, then look for a small floor switch that you step on to click on and off

Check at the headlight sockets for a bad ground.

Are these interior lights our the headlights? If it is the interior lights, you should pull the dimmer switch and check for a bad connection especially the ground connection on the back side. If that is okay, you may need to buy a new switch. If it is the headlights, check for a bad relay.

It's the dimmer switch in the column.