Truck to trailer plug??

[FFL8N]

Can someone tell me which contacts from the truck plug controll what on the trailer? I ran my batteries down low and could not start the generator on it in the morning. I plugged my truck in like I have with trucks in the past to "jump" the batteries, but it didn't help. Is there a hot wire from the truck to the trailer batteries?

 

[HBarlow]

Yes, there is a 12v hot or charging line in the seven pin connector but it is a small gauge wire. It would take a long time to equalize truck batteries to trailer batteries simply by plugging in to the seven pin connector.

I'm assuming you're talking about RV trailer batteries and a generator in your trailer.

Better method would be to park the truck alongside the trailer and use a jumper cable from truck to trailer with truck engine running at fast idle.

 

[FFL8N]

With my 2000 truck, I could plug it in and be able to start my generator if the batteries were just low. When I tried it with this truck, no extra juice from the 06? I want to know which wire is the hot to power the trailer so I can see if it is hot or not.

 

[icman95]

Try this link. Has a good diagram. I'd imagine the blue one labeled "fog light" might be the one since everything else seems accounted for.



Google Image Result for http://www.offroaders.com/tech/images/trailer-plug.jpg

 

[hilda]

Does your charge line work?

On new truck you may have a 7 way but that does not mean that it is working. Check the owners manual on your truck make sure all the fuses and relays are installed. Some trucks (durajunks) have a dummy fuse. We check every truck before the trailer is hooked up to it, the majority of newer truck have never had all of the fuses and relays installed. 4 pin black is your charge line.



Jim



RV Service Manager

 

[AClayton]

On new truck you may have a 7 way but that does not mean that it is working. Check the owners manual on your truck make sure all the fuses and relays are installed. Some trucks (durajunks) have a dummy fuse. We check every truck before the trailer is hooked up to it, the majority of newer truck have never had all of the fuses and relays installed. 4 pin black is your charge line.



Jim



RV Service Manager

My . 02 as well

 

[HBarlow]

Back to the original question. You don't really have to know which pin to check to determine if you have 12v present at the seven pin. Use a testlamp and check each pin to ground. The only one that should be hot with lights off and nobody's foot on the service brake would be the charge line. It you find 12v it works. If you don't find 12v then you know it doesn't and then you'll need to find out which pin should be hot and begin checking fuses.

 

[B.G. Smith]

Trailer/Towed Vehicle Wiring The hot (#4 wire) is the first one to the right of the top center of receptacle, the ground is 180 away from it. bg

 

[FFL8N]

Thanks everyone for your replies... I will start checking tomorrow. Again, thanks!!!

 

[RVTRKN]

It is in your owners manual, just remember it is the female receptacle on the truck and you won't want to get them backwards looking at the owners manual. Mirror image can reverse the pins and deceive you. If your eyes are bad get a magnifying glass and they are identified by the numbers and are molded into the plug. (4 blk).

 

[FFL8N]

Thanks again for all the info... It was right there on the plug. Lots of good info from everyone!! Bye the way, the power was there, so now I need to find out if the trailer is getting the power from the truck. I will start will the fuses!

 

[icman95]

If the power on the truck is there, then I had a similar problem the day I went to pick up my 5er up from the dealer. Turns out there is a junction box in the pinbox where all the wires from the trailer's pigtail meet. One of them was loose in the box and causing all sorts of problems. I didn't deal with the batteries, but the outside lights-tail, running, etc. The ground wire was loose.