No Power to Trailer from Tow Vehicle - Confirmed 12V at Truck Plug - 2007 SV 235RS

mikeroho · 05-23-2016, 04:46 PM

Hello,

I recently bought a 2007 Surveyor SV 235RS that is not getting any 12V power to the trailer from the tow vehicle (2004 Ford F-250). I have confirmed a 12V source at the truck plug with a multimeter, everything should be good at the truck end.

Inside the trailer with no battery or a dead battery, no lights work and I cannot operate my rear slide. Further, I am also not getting any power to my trailer battery to charge it when I drive.

I have read on this forum that there should be a fuse on the trailer side under the hitch for the 12V power, however, I cannot find it. I also cannot find where the 12V lead goes into the trailer to try and check any other fuses or loose connections. Can anybody confirm if there is a fuse at the trailer hitch or what else might be causing this? Is there another fuse I should be checking?

Thank you in advance.
Mike

Bowmanville SVT255S · 05-24-2016, 02:12 PM

Have you any power with shore power? Check battery connections

Bowmanville SVT255S · 05-24-2016, 02:13 PM

There are also a fuse and breaker panel in the coach

**Bama Rambler** · 05-24-2016, 02:23 PM

Keep in mind that the 'fuse' near the tongue won't look like a regular fuse. It'll look more like just a pair of terminals. It could also be located in a storage compartment or near the converter.

Toddupton · 05-24-2016, 02:29 PM

Also with no battery I don't think, even it the truck was putting the 12 volts out, that you would be able to run out your slide anyway. Way too many amps are needed and something would pop.

ScottBrownstein · 05-24-2016, 02:58 PM

Quote:

Originally Posted by Toddupton

Also with no battery I don't think, even it the truck was putting the 12 volts out, that you would be able to run out your slide anyway. Way too many amps are needed and something would pop.

agree, it might not pop anything but the leads are too long and too small to power much in the trailer. The lights, however, should work if by themselves. If they don't, something is wrong with getting the TV power to the rig.

HONDAMAN174 · 05-24-2016, 03:35 PM

Look for a 4" electrical box that your 7-pin harness comes into. Open that up and there should be a standard 30 amp fuse in there. Had same problem few weeks ago. Put a resettable fuse/circuit breaker in its place so I would never have to fix it again. Might as well check the connections on the two post circuit breaker that will be next to it.

2014 Evo 2850 "Woodstock"
2011 Toyota Tundra "Clifford"

DirtSquirt · 05-24-2016, 03:47 PM

Do your outside trailer lights work? When I went to pick up my trailer from storage this spring, I had the same thing happen. It seemed like no power to the trailer, the tongue jack wouldn't work, etc, but the brake lights and turning signals worked so I drove it home. I tested everything, fuses were good and it seemed like there was no reason it should not be getting power. I cleaned the contacts and it all started working again!

mikeroho · 05-24-2016, 10:53 PM

Thanks everyone for the replies, I appreciate everyone's help. Responses below:

Quote:

Originally Posted by Bowmanville SVT255S

Have you any power with shore power? Check battery connections

Yes, everything works when connected to shore power. When plugged into shore power, I have ~12 volts running back to the battery leads that charges the battery (confirmed with multimeter when battery disconnected).

Quote:

Originally Posted by Bowmanville SVT255S

There are also a fuse and breaker panel in the coach

Is this what you are referring to? (Picture 1)

If so, all fuses in here appear to be fine. Is there another fuse between here and the 7-pin plug?

Quote:

Originally Posted by Bama Rambler

Keep in mind that the 'fuse' near the tongue won't look like a regular fuse. It'll look more like just a pair of terminals. It could also be located in a storage compartment or near the converter.

I see nothing at the hitch before it goes into the trailer frame, then I lose it (Picture 2 and 3). Also see nothing in the front outside pass through storage. Is there any where else that FR puts these fuse boxes in the storage compartments?

Quote:

Originally Posted by ScottBrownstein

agree, it might not pop anything but the leads are too long and too small to power much in the trailer. The lights, however, should work if by themselves. If they don't, something is wrong with getting the TV power to the rig.

No lights work (other than brake, turn and running lights) or other devices (water pump, stereo fan...etc.) work when not connected to shore power when the battery is dead or disconnected. I definitely have power at the plug on the TV (Picture 4). It's just not getting into the TT.

I do not intend to run any appliances or the slide with only the TV power. I would like it to charge the battery when driving or use interior lights if needed when the battery is dead and I have no shore power.

Quote:

Originally Posted by HONDAMAN174

Look for a 4" electrical box that your 7-pin harness comes into. Open that up and there should be a standard 30 amp fuse in there. Had same problem few weeks ago. Put a resettable fuse/circuit breaker in its place so I would never have to fix it again. Might as well check the connections on the two post circuit breaker that will be next to it.

I see nothing at the hitch before it goes into the trailer frame, then I lose it (Picture 2 and 3). Also see no electrical boxes until the breaker panel. Do you know where this is located on a SV 235RS?

Quote:

Originally Posted by DirtSquirt

Do your outside trailer lights work? When I went to pick up my trailer from storage this spring, I had the same thing happen. It seemed like no power to the trailer, the tongue jack wouldn't work, etc, but the brake lights and turning signals worked so I drove it home. I tested everything, fuses were good and it seemed like there was no reason it should not be getting power. I cleaned the contacts and it all started working again!

Yes, all outside light (brake, turn and running) work fine. The plug contacts appears clean.

Thanks again for everyone's help. Sorry for the long response. I need to try and trace the wiring in to the trailer. Does the paneling come out east from underneath the trailer, between the frame rails (Picture 3)?

Bluepill · 05-24-2016, 11:05 PM

Some trailers have a circuit breaker in the red (positive) power line attached under the frame. If so, remove the red cover to find the reset button.

mikeroho · 05-25-2016, 12:03 AM

Quote:

Originally Posted by Bluepill

Some trailers have a circuit breaker in the red (positive) power line attached under the frame. If so, remove the red cover to find the reset button.

Thanks Bluepill. I am sure that is the problem, I just need to find that fuse! From the 7 pin plug to the trailer, I cannot find it. Once it goes into the trailer, all of the wiring is located below the floor, between the frame, which is covered on the bottom as well. Do I need to access this area you think? See picture. Thanks again.

**Bama Rambler** · 05-25-2016, 08:13 AM

That cable should go into a junction box mounted in the front of the RV. That's where it's hooked to the RV wiring for lights and brakes.

It may be located behind a panel in the front storage area.

ScottBrownstein · 05-25-2016, 08:30 AM

When on shore power, is there 12 volts on the TT pin that goes back to the TV (Pin 4)? The running lights and turn signals are fed separately from the house battery charge pin. I am sure that you already know this but thought I would ask. The answer is probably no and that indicates that something (fuse, breaker, etc) is open on that lead between the house DC panel and the TT cable.[IMG]http://i5.photobucket.com/albums/y20...ps702153a8.jpg[/IMG]

awellis3 · 05-25-2016, 11:21 AM

Quote:

Originally Posted by Bama Rambler

That cable should go into a junction box mounted in the front of the RV. That's where it's hooked to the RV wiring for lights and brakes.
It may be located behind a panel in the front storage area.

I agree. Mine on the Rockwood is on the frame about where your harness disappears. I agree with Bama, it has to be somewhere and you'd think it would be accessible.

nineback · 05-25-2016, 11:49 AM

If you have a battery disconnect switch somewhere make sure it is turned on. Mine is in the storage compartment.

Tom

mikeroho · 05-25-2016, 01:14 PM

Quote:

Originally Posted by ScottBrownstein

When on shore power, is there 12 volts on the TT pin that goes back to the TV (Pin 4)? The running lights and turn signals are fed separately from the house battery charge pin. I am sure that you already know this but thought I would ask. The answer is probably no and that indicates that something (fuse, breaker, etc) is open on that lead between the house DC panel and the TT cable.[IMG]http://i5.photobucket.com/albums/y20...ps702153a8.jpg[/IMG]

ScottBrownstein - I never did check if I have 12V going back to the TT plug. I understand the brake, turn and running lights work on a separate system. I just took the trailer back to storage for a couple weeks, I will check that when I get it back. Should I have 12V going back to the plug when connected to shore power?

Thanks for the input.

mikeroho · 05-25-2016, 01:16 PM

Thanks everyone else for the input. I just took the trailer back to storage for a couple weeks. I had to get it off the roadway. When I get it back, I will double check the storage compartment again, if it is not there. I will attempt to take off the underside flooring/paneling on the frame to see if I can trace it.

Thanks again.

raspivey · 05-25-2016, 01:25 PM

You mentioned "when the battery is dead or disconnected". What is the voltage on the battery? The battery may be toast.

ScottBrownstein · 05-25-2016, 01:54 PM

Quote:

Originally Posted by mikeroho

ScottBrownstein - I never did check if I have 12V going back to the TT plug. I understand the brake, turn and running lights work on a separate system. I just took the trailer back to storage for a couple weeks, I will check that when I get it back. Should I have 12V going back to the plug when connected to shore power?

Thanks for the input.

Yep you should if there is a path for the TV to charge the TT batteries. Works both ways and I would expect that there isn't any voltage on pin 4 to ground. Just a thought. If there is voltage then your problem is not in the TT, but I bet there isn't and it is in the TT.

hillsdaletc · 05-25-2016, 02:14 PM

You will find your junction box just above the plastic belly panel where the cord goes through it. If you cannot easily pull down the panel. you can cut it with a razor knife and make a flap to open for access. Black Gorilla Tape works excellent to seal it back up. Do NOT use duct tape it wont hold. Breaker should be in the box.

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