Do I need power at pin 4 on my tow vehicle?

[RAMwoodworks]

I think y'all think I be dumb. I know I need to plug that big black rubber thing on my trailer into my truck (what else will keep the trailer from falling off the ball ;))

This year we're going to take a few trips all within 100 miles. Any place we go will at a minimum have water & electric. I do plan on running the fridge on propane on the way down to keep it cool. I will pre-cool it on shore power before hand.

So since I'm taking short trips and will have electric when I arrive do I need to hook up the power from TV to my 7 pin for the short trip (2-4 hours)?
Update: What I mean is my Tow Vehicles do not currently have power at pin 4. So while towing my TV will not charge the RV battery.

Also, do I need to have a battery disconnect?
The only thing running when sitting at my house is the propane/battery detector and the radio. During winter the battery will be brought inside to keep from freezing.

[RAMwoodworks]

Terryallan wrote:

RAMwoodworks wrote:


Update: What I mean is my Tow Vehicles do not currently have power at pin 4. So while towing my TV will not charge the RV battery.

.

Think y'all misunderstood , or missed this part, or it wasn't there..

But yes it would be a great thing to charge the TT while towing. Always a chance the battery could die, as the refer has to have power to run even on propane. A light could be left on, whatever. Should that happen. The refer will cut off. With the charge pin powered. The TV will power the refer. Depending on your TV. It should be an easy fix to put power to the TT charge pin.

On Fords there is a relay that must be installed to charge the trailer. not real sure about the others. The first thing I would do is find the trailer fuses in the fuse box in the TV, and check them all to see if any are missing, or blown.

Both my TVs are GMs and they just need a fuse installed. They come with a dummy fuse in the spot that powers pin 4.

I'd really like to have a look at a 12V wiring diagram for a TT. From what I understand you can jump pins 3&4 on your trailer plug to turn on running lights while on shore power. This and the breakaway switch powering the brakes means that the TT battery is not isolated from TV even if pin 4 is deactivated.

[RedRocket204]

I see nothing to support the comments that on a RV 7-way trailer plug that pin 4 is required for brake/signal/running lights.

It appears Pin 4 is strictly an AUX pin for charging the 12V trailer system batteries and for providing 12V power to the trailer. However, this would be critical back-up 12V power for the trailer break-away system and also as mentioned, for your refridge running on propane.
etrailer.com - Trailer Wiring Connectors

[Terryallan]

RAMwoodworks wrote:


Update: What I mean is my Tow Vehicles do not currently have power at pin 4. So while towing my TV will not charge the RV battery.

.

Think y'all misunderstood , or missed this part, or it wasn't there..

But yes it would be a great thing to charge the TT while towing. Always a chance the battery could die, as the refer has to have power to run even on propane. A light could be left on, whatever. Should that happen. The refer will cut off. With the charge pin powered. The TV will power the refer. Depending on your TV. It should be an easy fix to put power to the TT charge pin.

On Fords there is a relay that must be installed to charge the trailer. not real sure about the others. The first thing I would do is find the trailer fuses in the fuse box in the TV, and check them all to see if any are missing, or blown.

[RedRocket204]

BTW, didn't see it mentioned...

You can install a battery disconnect and have your battery disconnected when the trailer is sitting stored at home and not plugged in. This is a good thing for battery life.

However, do not have your batteries disconnected when you are towing. The break-away brake system on your trailer requires 12V battery to activate the brakes in the event your trailer detaches from your tow vehicle.

As for active power on pin 4, you really should have that power available. What would you do if your batteries were drained and you needed to tow? Having that power available will make you legal with regards to having the power back into the batteries for your break-away switch to properly activate the trailer brakes.

[trail-explorer]

JimVan wrote:
You will need to have it plugged In so your break lights and turn signals will work

DITTO.

JimVan wrote:
break lights

BRAKE LIGHTS, not break lights

[trail-explorer]

DutchmenSport wrote:
When driving, your 7 pin plug needs to be plugged in all the time. That plug is needed for your trailer turn signals and brake lights, as well as a power line for tow vehicle battery to the DC volt system in the trailer.

DITTO

[trail-explorer]

DavidP wrote:
Yes, you need to have your 7 pin connected. This is very important if your trailer has brakes which I assume it does. If not connected you have no brakes. Also, your fridge if DSI will need 12 volt as well to operate on propane.

DITTO

[downtheroad]

I understand that this was a serious question....and you have gotten many correct answers
But, why would you not hook up your connector? It does a lot more than just charge your battery.....it does stuff that is absolutely vital to your safety when towing.

[JimVan]

You will need to have it plugged In so your break lights and turn signals will work

[DutchmenSport]

When driving, your 7 pin plug needs to be plugged in all the time. That plug is needed for your trailer turn signals and brake lights, as well as a power line for tow vehicle battery to the DC volt system in the trailer.

Once at your campsite, or when parked, you unplug the 7 pin connection.

You do not need a battery kill switch on your camper. It's not necessary. Kill switches are used for just that ... to kill any battery draw or parasitic draw your camper does on your battery when you are not plugged into shore power. When plugged into shore power, the converter in your camper will power all the 12 volt systems and keep the battery charged. Flipping the batter kills switch disconnects the battery and will not charge. But the converter inside the camper will still run your 12 volt items. Still, it's better to keep your battery active (not disconnected) so all 12 volt items draw power from the battery and the converter.

The only exception here is, may be your slides. The converter by itself is usually not enough power to move the slides. They need the battery. If your battery kill switch is in kill position, your slides and maybe your power awning will not operate.

And by the way ... if your battery is on your camper in the winter, and your camper is plugged into power, the trailer converter will keep the battery charging all winter. Like in your automobile, as long as the battery is charged, it won't freeze or get damaged, unless it gets like, a million degrees below zero or something.

[DavidP]

Yes, you need to have your 7 pin connected. This is very important if your trailer has brakes which I assume it does. If not connected you have no brakes. Also, your fridge if DSI will need 12 volt as well to operate on propane.

I would install a battery disconnect as well. Your propane detector and anything that has parasitic draw will kill the battery in no time.