'73 FJ40 Marker Lights went out

[cvan1971man]

The side marker lights on the tub have gone out. Wondering if there is a common cause - i.e. switch, etc.

All other lights work. That is the problem, why just the marker lights.

 

[pb4ugo]

Have checked to see if the bulb is blown? What testing have you done?

 

[cvan1971man]

Have checked to see if the bulb is blown? What testing have you done?

It is both sides. I guess both bulbs could have blown. It would be odd for both of them to go at the same time.

 

[pb4ugo]

There's a plug in the back of the right rear wheel opening. Check for continuity with a test light. Start at the light socket and then chase it forward till you find power.

 

[cvan1971man]

There's a plug in the back of the right rear wheel opening. Check for continuity with a test light. Start at the light socket and then chase it forward till you find power.

That is what I needed. Appreciate you.

 

[pb4ugo]

Do the taillights work?

 

[cvan1971man]

Do the taillights work

All other lights work except for the side marker lights

 

[pb4ugo]

Taillights and side marker lights and license plate lights are part of the same circuit.

 

[cvan1971man]

Taillights and side marker lights and license plate lights are part of the same circuit.

Hmmmm. Taillights and license plate lights work

 

[B y r o n]

Check for grounding issues. Just because a ground wire is bolted to the body/frame doesn't always mean it has a connection. Rust can form blocking the circuit and these need periodic cleaning. Undo the ground wire and clean it and where it contacts with a stainless brush and put back together.

 

[cvan1971man]

Check for grounding issues. Just because a ground wire is bolted to the body/frame doesn't always mean it has a connection. Rust can form blocking the circuit and these need periodic cleaning. Undo the ground wire and clean it and where it contacts with a stainless brush and put back together.

wouldnt a faulty ground cause the tail lights and license plate light to fault as well?

 

[Green Bean]

If you are not already familiar, in my opinion the perfect tool for diagnosing electrical issues such as this is a Power Probe. It tests for both voltage and ground and it supplies 12v+ to a circuit. With the factory bullet connectors on the marker lights it is really fast and convenient to simply unplug the light and test for current or supply 12v to the light to test the fixture.

Amazon.com

 

[rlong]

wouldnt a faulty ground cause the tail lights and license plate light to fault as well?

No each fixture needs it’s own ground..

It has been said time and again MOST electrical issues are bad ground.

 

[cvan1971man]

If you are not already familiar, in my opinion the perfect tool for diagnosing electrical issues such as this is a Power Probe. It tests for both voltage and ground and it supplies 12v+ to a circuit. With the factory bullet connectors on the marker lights it is really fast and convenient to simply unplug the light and test for current or supply 12v to the light to test the fixture.

Amazon.com

Cool, never heard of a power prove. Will check into it.

 

[pb4ugo]

Has those lights ever worked since you've owned it?

 

[cvan1971man]

Yeah, they worked great.... until they both didnt! When my son gets home tonight i am going to get after it with a voltimeter

 

[pb4ugo]

Its odd they both went out at the same time and the other running light still work. They should be wired separately. Rear wiring gets altered by PO's all the time. Typically wires are run from the trail lights up to the side markers. The fixture has 2 wires, 1 is a short lead for the ground and connects to the lens/fixture mounting screw inside the tub with a nut. The other comes up from the tail light/plug.