1998 Chevrolet s10 - No daytime running lights or dim lights. Bright lights work. Changed dimmer/ turn signal switch assembly and checked all relays, fuses, and diode. Help!!

The dimmer switch only works when the headlights are on, When they are off there is a light sensor on the dash that takes over and adjusts the dash lights as needed. It sounds like yours has gone out.

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is it adjusted by the light switch left on bright right dim all when lights are on all dash lights will dim thats normal

Daytime headlight issue ? No , no sensor behind the front bumper . No Daytime time head lamp issue , doesn't turn on the instrument panel light's . This is more then likely a remote dimmer module problem .
Interior Lights Dimming Circuit Description (Pontiac)
When the park lights are on, battery positive voltage (B+) is applied via CKT 32 (YEL) to the remote dimmer module. The interior dimming switch in the lamp dimmer switch is a variable resistor which applies the dimming input via CKT 44 (DK GRN) to the remote dimmer module. The potentiometer in the lamp dimmer switch cannot provide enough current in order to operate the incandescent lights. The remote dimmer module amplifies the current, applying a variable voltage to the incandescent lights. As the amount of current increases, the lamps become brighter. As the amount of current decreases, the lamps become dimmer.
The radio, heater and A/C control assembly, instrument cluster, and passenger climate control each has a vacuum fluorescent (VF) display. When each module receives an input that the ignition switch is turned to the RUN position, each module activates the VF display at the full intensity. When the park lights are on, the radio receives the dimming level from an input on CKT 8 (GRY). The radio then relays this information to any other modules with VF displays. All modules with VF displays then adjust the dimming level of their VF display in order to match the level of the incandescent lamps.

It sounds like the dimmer switch is getting bad. . I've also seen the daytime running lights causing this. Look in the owners manual, find out if the lights have a separate switch to turn them off. If you do have a switch, turn it off and see if you get low beams. Do your daytime running lights work? Have a look at that first. An auto electrician can test that curcuit pretty easily if you cannot get it solved Hope this helps good luck. please rate this solution.

I had a similar problem with my Camry that the light will go out when I go from dim to bright. I found that in the dimmer switch contacts there is a small plastic piece that runs through one or two contact to operate a set of contact. Mine was broken. Seeing that you have a new switch it could be that yours are maybe not correctly in place - that is if it works the same as a Camry's.

DIMMER SWITCH OUT OF ADJUSTMENT.I SEEN CAR WITH SAME PROBLEM THEIR HIGH BEAMS WOULDNT WORK.THE DIMMER SWITCH AND BULBS WAS GOOD.IT TURNED OUT TO BE DIMMER SWITCH NEED TO ADJUSTED.

If the fuses or brake light switch were bad your third brake light would not work same with the multi purpose switch. you either have a wiring problem like some broken wires or the actual light sockets are bad. it is common with gm trucks that the circuit board for the tail lights melts and does not make contact.

First thing i would do is chg. the break light switch, and make sure to chk. all grounds around tailights, sometimes if there is a ground problem it will travel back thru the hot wire to get a ground, witch in turn makes everything go wackey.

the inner lights are the brights but some vehicles also use the bright lamps with low voltage as the daytime running lights

If you have replaced the switch, and it is still doing it it sounds like you definately have a short somewhere in your wiring. On the other hand if the dimmer is in the turn signal arm ( forward bright back dim ) the problem could also be there in the dimmer switch, such as a short being caused by that dimmer switch being faulty.Auto Zone and Discount Auto Parts both test a lot of your electrical problems for free, and/or may have some knowledge to more accurately pin point the problem. Not sure about Pep Boys or some of the other discount auto part chains.