How do I know if the instrument lights on my 1993 Ford Ranger don't turn on when my headlights is because the bulbs are bad or if I have a wiring issue?

Although you say you tested it for power, and the bulb is good, I am almost certain it you change the bulb it will work. The one at the back. Take the one from the right side and try it in the left. Then you'll know. If there is still nothing and your test light shows power, it has to be a bad ground wire. If you have an aftermarket trailer plug on that thing, that will be another place to look.

Hello,

To remove the front head light please follow the steps below:

1. Place the Ford Ranger in "Park." Turn the engine off. Turn the headlights off. Remove the key from the ignition. Allow the truck to cool for about 20 minutes.
2. Open the hood of the vehicle. Locate the two retainer pins on the headlight assembly of the light that needs to be replaced. Pry the retainer pins open with your finger. This releases the headlight assembly from the Ranger.
3. Pull the headlight assembly forward. Unplug the electrical connector from the back of the assembly by hand. Rotate the retaining ring counterclockwise and slide it off the plastic bulb base.
4. Pull the burned out bulb straight out of the headlight assembly. Discard the used bulb. Insert a replacement bulb into the headlight assembly and push it straight into the socket until it clicks into place. Slide the retaining ring around the bulb and rotate it clockwise to secure it.
5. Plug the electrical connector into the back of the unit. Slide the headlight assembly back into the Ranger. Push the retaining pins back down to secure the headlight assembly.

Hope this helped. thank You for using FixYa!!!

The procedure is as follows:---First you need to open the hood and twist the bulb socket out from the lens.1)Remove the screws retaining the headlight and trim assembly.
2)Carefully rotate the headlight and trim assembly away from the vehicle, rotating the inboard side away from the vehicle.
3)Remove the side marker, parking and turn signal bulbs and sockets from the headlamp and trim assembly. They can be removed by turning them.
4)If replacing a lens, remove the retaining screws for the lens to be changed and remove it from the headlight door.
--------- Thanks.Helpmech.

broken ground wire

you might have blowed blulbs check that also there might be what is called a fuse link in the wiring

Look under the hood.
There is a large relay which should have some info about lights on it.
I had this exact problem with my dodge ram

You have a bad ground, look out by the battery for a bunch of black wires screwed to the body of the car, check that they have a clean and tight connection, scrap off any paint under the wires.

In your wiring harness you have a brown wire, that is your tail and marker lights. The green wire is your right turn. And the yellow wire is your left turn. Don’t forget to add a ground wire. If you are installing a brake controller, run a blue 10 gauge wire to the trailer plug.

check your head light switch