Replacing marker lights

[mattyj858]

Hey guys,
I have been reading through the posts on replacing clearance/marker lights and in the process of replacing them.  I am replacing the rusty screws and cleaning the holes for a good ground. Some still don't work. I have chased the wiring as best as I can and don't see any chaffed wiring. Also inspected back by the chassis and the battery box. Checked and replaced fuses below drivers side cab, are there other fuses besides that fuse box?
Is there a test to see if I am getting power to the wire? I have a meter but honestly not very knowledgeable about electrical beyond the basics. If there's a test through a meter can anyone explain? Hat settings on the meter ect? My meter is the basic Harbor Frieght red and black wire connected to box with volts, DC and OHM


Any suggestions is greatly appreciated. Getting close to getting the old rig back on the road

[Froggy1936]

Each light should have a hot wire and a ground wire (The screws do not have to ground) Also if you are installing LED,s They will not work if wired backwards When Checking set meter to 20 direct current volts Use red to hot and black to ground Some Manufacturers may use any color wires they had available so don't depend on original wire colors !  D:oH! Frank

[mattyj858]

Each light should have a hot wire and a ground wire (The screws do not have to ground) Also if you are installing LED,s They will not work if wired backwards When Checking set meter to 20 direct current volts Use red to hot and black to ground Some Manufacturers may use any color wires they had available so don't depend on original wire colors !  D:oH! Frank

These marker lights only have one wire. I only have one wire coming from the RV and one wire for the lights? These are not LED
I tested the current with meter set at 20 DC, red lead on the hot wire and the black on the set screw in the sheet metal, reading is .35 is that too low to allow the bulb to light?

[Rickf1985]

Yes it is, you have a bad connection somewhere. the lights on mine are single wire in some places and two wire in others. If it is single wire than the mounting screw is the ground. Put the ground lead of your test light on a good ground, something on the frame preferably. If you have a set of jumper cables then hook the black jumper cable to the ground cable on the battery and then hook your test light ground to the other end of the jumper cable. That is the best way to bypass all bad grounds. If you cannot reach the battery then find a clean spot on the engine or transmission or a clean metal bolt on the body in the cab area. You want a good clean ground for the test light. If the test light show the the bulb and socket are good then hold the screw against the jumper cable if it will reach (this is a good time for some of those wires with the alligator clips on the ends from Radio Shack), The light should come on. If it does but will not come on when mounted on the body there may be an issue with the body being grounded. Corrosion gets in the seams and breaks contact.

[mattyj858]

Thanks Rick finally was able to get most of them working. Now the task of finding 2" replacement markers for the front and rear.....