Signature porch light

[jriedel]

I have a 03 Signature & just tried a new thin lite porch lite. There is no power @ the wires @ the fixture & the fuse in the bedroom cabinet is not blown. The indicator light on the switch does not come on either. Is there a relay or something else in the circuit?

[K7JV]

It is not a normal way of "doing business", but in this case it is very likely that they are switching the ground rather than the hot lead. On our '06 Dynasty, the grab handle lights and the basement lights are all controlled by switching the ground. I don't have a schematic for our porch light, but my bet is that it is the same way. The reason is that ground may not be readily available at remote locations like those, in our fiberglass boxes.

That may affect how you take your voltage readings as you troubleshoot. If you could check for voltage at the wires/fixture to a ground, like a bare screw on your door jamb, you might be able to narrow your search. I would expect a conductor from the fuse location to the light fixture, and a second conductor from the fixture to the switch by your passenger seat. The switch would then tie it to ground to turn "on" the light(s).

I hope your replacement light works out well for you.

[Thunderfoot]

Originally Posted by K7JV

It is not a normal way of "doing business", but in this case it is very likely that they are switching the ground rather than the hot lead. On our '06 Dynasty, the grab handle lights and the basement lights are all controlled by switching the ground. I don't have a schematic for our porch light, but my bet is that it is the same way. The reason is that ground may not be readily available at remote locations like those, in our fiberglass boxes.

That may affect how you take your voltage readings as you troubleshoot. If you could check for voltage at the wires/fixture to a ground, like a bare screw on your door jamb, you might be able to narrow your search. I would expect a conductor from the fuse location to the light fixture, and a second conductor from the fixture to the switch by your passenger seat. The switch would then tie it to ground to turn "on" the light(s).

I hope your replacement light works out well for you.

Good advice here ^^ as there are numerous circuits where the ground is switched on my '98 Sig....

[RobRoy]

Most automotive is switched on the ground such a lighting and fuel injectors and you have received some pretty good advice so far.

I will say that it seems no two coaches are the same and that you better make sure that you have a good ground source. I have a 50ft wire to go all the back to the battery if necessary ( most cases not) for my test light or DVOM

Power probes http://www.powerprobe.com/ are very nice for diagnosing electrical issues. I personally don't have one, but it certainly would be handy for a lot of issues on these coaches as you can power up and ground circuits quickly.

If you have no power at the fuse on either side, you know need a wiring diagram to see what feed that fuse you are referring to.

You can also jump 12v to the hot side of the thin lite with a 5amp fuse and see if the lite works? if so it's a 12v power issue and while still connected you can check that circuit back to fuse panel..... it should be 12v if not? you have an open in the 12v power lead.

You can also jumper with 12v with a in-line fuse 5amp fuse to your fuse panel source, and that would be telling as to what direction to go

Happy Hunting

ps I just replaced my porch lite / thin lite with led strips the cost was @ $5.00 total

[Mike Canter]

The porch light wires run into the passenger side console and it is possible that the wire has come loose down in there. Mine did.

[Jeff753]

I had a bad ground at the fixture which you could eliminate as a possible issue by running another wire to the battery ground. Then you would know if it's a problem on the positive side.

[Johnontheroad]

Just as a side note, Amazon was running a special of a motion controlled solar porch lite. It was around $8 including Prime shipping. It has a small solar cell, battery, motion detector and bright LED lights. Looks like any porch light.

Works like a champ, light comes on whenever there is motion near the door, stays on for 20 seconds or so, then turns off. No wiring, no switches, no problem.

Look here:

[URL="https://www.amazon.com/gp/product/B00W135S4M/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1"]