I am trying to hook up my tow lights on a 1979 travel trailer to my 2000 Ford F150 with the 7-pin connector. I have looked at diagrams and nothing matches. I don’t know if the problem is with my truck, the travel trailer, the connectors or what. At first I thought everything worked except the left turn signal, which would flash both right and left lights. After looking further it appears that some lights are brighter than others indicating that some were brake lights while the other side was running lights or taillights.

I checked my F150 to see what was going on at that connector and discovered it was a Hoppy 7-pin connector with a 4 pin flat connector built onto the left side all made together. This Hoppy connector is plugged into what I suppose is Ford factory wiring. I checked the 7 pins coming out of the Hoppy and found 12 volt working well but did discover that when I turned on my left turn signal that 2 of the 7 pins would flash indicating that this may be my problem? ( I suppose one of these may have been for the 4 pin side connector but its in the 7-pin connector?)

Here are my questions?
Has anyone else checked a 7-pin connector on their F150 and got 2 poles sending out the same signal at the same time?
I think 2 pins giving out voltage at the same time is a bad thing, what you think?
Should I go get another 7-pin connector and put it on my F150 truck and try it?
It there another way to do this wiring, like hook up one wire at a time starting with a turn signal and then the other signal and then tail lights etc?
Thanks,
mtnman

 

Check the wiring on the truck. It sounds like you have some wires touching in the plug wiring. It doesn't have to be a large chaffed place, sometimes it's as little as a couple of strands touching. Take it apart and check it out real close.
Good luck.
Joe

 

It really sounds like you have a bad ground more than anything else. Without the ground, the electrical finds all different ways to make a completed circuit causing the taillights and turn signals to go on when they should be off, etc. Clamp a jumper cable from the tow vehicle to the trailer and see it you get better results (connect metal frame to metal frame).

 

Clamp a jumper cable from the tow vehicle to the trailer and see it you get better results

I did that and it still fails. I need to know if anyone else has actually checked their 7-pins and what kind of reading they got? As I stated earlier, I checked the 7 pins coming out of the Hoppy on my truck and found 12 volt working well but did discover that when I turned on my left turn signal that 2 of the 7 pins would flash indicating that this may be my problem? Is there a place on the forum that says what should read off each pin on the 7-pin plug? Someone said I needed an adpter between the wiring harness on the truck and the 7-pin connector?
mtnman

 

Try this site. It's for an RV 7 pin, but they all should be standard. You just have to trace the wiring on your truck.

http://www.marksrv.com/wiring.htm

 

Sherpa,

Sounds miswired. I know on my 1971 Ford I used a Hoppy tail lamp converter module along with the 7 pin/4 pin dual combo thing from www.northerntools.com.

They sell the Hoppy converter at Advance Auto and if wired correctly it will allow the current to only flow down the wires it is suppose to each connector (7 wire/4 wire). It is marked as for vehicles with separate turn signal lamps and Ford vehicles.