Running lights wont work

[A Inkster]

We recently redid the wiring in our 74 Trillium. The brake and turn signals work but the running lights don't. We replaced the original running lights with Grote Clearance Markers 46712 & 46713. Voltage meter shows 13v at the new unit, when we put the wires to the bulb it lights up but when we put the bulb in the unit it wont work. Any suggestions???

[mary and bob]

Those lights have to be grounded, normally by one screw that goes through the ground strap in the light. Did you run a ground wire to each light?

[A Inkster]

Yes, we did, thank you for your reply

[mary and bob]

Can you post a picture of the wiring at the lights

[Dan Meyer]

Can you measure the voltage with the light bulb installed?

--Dan Meyer

[RogerDat]

If they be LED lights they care about the current direction positive to negative. Regular incandescent bulbs don't. Just a thought if they are LED try reversing the wires or the bulb connections. Or use jumper wires to test would light work with wires reversed.

[mary and bob]

I looked up those lights and they are common marker lights with incandescent bulbs. I've used them many times. This info is assuming the google search image is correct. I'm sure I have some in my inventory if I go look. Also sure this is a simple fix, but can't see it from here

[RogerDat]

Originally Posted by mary and bob

I looked up those lights and they are common marker lights with incandescent bulbs. I've used them many times. This info is assuming the google search image is correct. I'm sure I have some in my inventory if I go look. Also sure this is a simple fix, but can't see it from here

Then I go with cheap base and socket not allowing contact. I have one on my camper that the disk with the center contact does not always make contact. Have had a few where the center contacts just did not reach the bulb with contact solid enough to run.

Had one with one of the wires connected to metal tab and the tab was just not solidly on the bulb contacts. That one was the most annoying PO... junk. Because it looked ok. Just this one part inside the case needed to be tweaked, pushed or twisted to make contact from wire to socket. Forget how I spotted it but now that I think back to were I was working that was a marker light.

Brain drawing on reserve power but I think the tab might have stuck up and was intended to contact a side pin of the bulb, the notch where it latched? Can so clearly remember the entire string of expressions I used when I figured out why it would not light. But what it was? Eh not so much.

[mary and bob]

OP said none of the lights work, so I more suspect a wiring issue or connection problem. But odd that he is reading voltage in the wire at the light. Image shows it uses the flat base push in bulb, number that I can't remember right now. I'm more curious as to how he attached the ground wire to the light

[A Inkster]

Sent from my iPad using Fiberglass RV

[Keaner]

When you say '13v at lights' are you measuring across a lit bulb, from positive to frame, positive to neg wire...etc?

[mary and bob]

I'm thinking you have a light similar to this, with this type bulb, but only a single bulb socket. So a couple questions, does the ground wire have good contact with the ground in the light as pointed to. Is there good ground continuity all the way back to the tow vehicle. I still believe it's a simple solution, but where the problem is, is not easy to diagnose from afar

[mary and bob]

Above photo is a light that has two bulbs in it, one is removed

[A Inkster]

Thanks all for your comments. It ended up being a problem in the pigtail coming from the truck. All is good now and we are ready for night driving!

[mary and bob]

Glad to hear problem is solved