DC Voltage Drop

[Jchaney]

I purchased a 2008 Rockwood HW276 and it was disclosed that a couple of the interior dome lights have gremlins.

First let me apologize for any grammar or spelling errors. I am posting from my phone.

Troubleshooting to date. Two of the rear most lights work. I can plug the fans in and they work. The fans above the galley and the front bunk do not. No fan power and no lights.

I used my multimeter and verified resistance. .01 on each light.

I then removed the bulbs and tested dc voltage. The bad lights have a voltage anywhere from 6-8 volts. The lights that work I have dc voltage at 11 vdc.

I assume I have a corroded connection or a bad ground somewhere causing the voltage drop.

Where are some common culprits to look for poor grounds? I did note that the voltage was higher at the galley light (8 vdc) than the front bunk light (6vdc)

Lastly the rooftop fan does not work. Not sure if this is related.

[flyerdp]

Originally Posted by Jchaney

I purchased a 2008 Rockwood HW276 and it was disclosed that a couple of the interior dome lights have gremlins.

First let me apologize for any grammar or spelling errors. I am posting from my phone.

Troubleshooting to date. Two of the rear most lights work. I can plug the fans in and they work. The fans above the galley and the front bunk do not. No fan power and no lights.

I used my multimeter and verified resistance. .01 on each light.

I then removed the bulbs and tested dc voltage. The bad lights have a voltage anywhere from 6-8 volts. The lights that work I have dc voltage at 11 vdc.

I assume I have a corroded connection or a bad ground somewhere causing the voltage drop.

Where are some common culprits to look for poor grounds? I did note that the voltage was higher at the galley light (8 vdc) than the front bunk light (6vdc)

Lastly the rooftop fan does not work. Not sure if this is related.

Interesting problem. The wires in the roof originate at one of the lifter posts going up the inside of the tent fabric and branch out to the lights and connector sockets (if you have those too). There is a pos. and neg. wire so there really isnt a "common ground" like your car frame. Its all wires all the way on your trailer. I'm at a loss on the voltage drop I am afraid unless its like Christmas lights where each light shares a part of the voltage and are connected in series. That though should be evident because one bulb removed would knock out all downstream from it so they are most likely wired in parallel.

[TacomaJoe]

Here's my 2 cents worth. Find your power panel and you may be able to see the bundle of wires connecting to it. The fuse layout may also give a clue. You have three different voltages up there and I'm not sure of the wire count going up, that's where the fuses come in. If it looks like only one fuse is labeled for upper lights/fans then I suspect that there is a poor connection in the upper wiring. There may be a switch that automatically cuts the power going up so everything is dead when the top is down. A bad connection somewhere, you have some power so I don't think it's a fuse. Eyeballs are probably your best trouble shooting tool here.

[Jchaney]

Thanks for the suggestions. I also checked the switch on the the outside corner. It functions properly. I feel like if the wiring is ran through the top to each light there shouldn't be any thing to check there.

I should add that the fans do not get power when plugged in with the headphone looking jack. I think I am going to disconnect those from the light fixture and recheck voltage.

I'm not looking for things in common. Yay! Troubleshooting.

[MohicanJeff]

I would test power at the switch first with the wires removed, verify the voltage and jump the two wires together to bypass the switch. Providing the voltage is near 12 volts (If not check fuses), I would then disconnect the fan from the circuit and test for the same voltage. I would leave the wires to the fan off and wire nut them separately. If the voltage is still inconsistent at the lights start by disconnecting the wires and test voltage at each light fixture. These things are annoying and take time to trace down but it sounds like you have a short to ground. Keep us posted on progress.

[Jchaney]

Easy fix. I started at the light with the lowest voltage (pictures included). Since there is no ground I decided it is probably connection related. The connections are these blue clip on connector that splices the wire. I disconnected them and was left with the loop of wire. I spliced them together and checked the voltage. 12.7 VDC as expected. The light above the galley then turned on with no issue. Checked voltage. 12.7 VDC. I soldered everything together and reconnected the light fixture and all lights work!

I also replaced all the incandescent bulbs with LED replacements.

The fan not turning on was due to the lid not being open enough. I have a replacement Propane, CO detector coming in (Home Depot had the exact same one as my local RV dealer for half the price.

All that's left is to wait until we are above freezing and start sanitizing the tanks, checking the axles and bearings and we will be enjoying this all summer long!

[flyerdp]

Originally Posted by Jchaney

Easy fix. I started at the light with the lowest voltage (pictures included). Since there is no ground I decided it is probably connection related. The connections are these blue clip on connector that splices the wire. I disconnected them and was left with the loop of wire. I spliced them together and checked the voltage. 12.7 VDC as expected. The light above the galley then turned on with no issue. Checked voltage. 12.7 VDC. I soldered everything together and reconnected the light fixture and all lights work!

I also replaced all the incandescent bulbs with LED replacements.

The fan not turning on was due to the lid not being open enough. I have a replacement Propane, CO detector coming in (Home Depot had the exact same one as my local RV dealer for half the price.

All that's left is to wait until we are above freezing and start sanitizing the tanks, checking the axles and bearings and we will be enjoying this all summer long!

Nice congrats! Glad it was easy to repair!