I have no turn signals at the pins on my factory install trailer hitch. All lights work at the rear of the truck,when I check t he pins I have good running lights,brake lights, but no turn signals right or left. They do work properly at the rear of truck. Any thouhts would help,Wayne

 

You have brake lamps at the 4 pin / 7 pin trailer tow adapter, but no turn signals on those pins ( it is a stop / turn circuit ) ?

If you have brake lamps on those pins, but it does not flash, you know the trailer tow adapter fuses are good.

 

Thanks for the response. I may have not explained the problem correctly. At the rear of the truck I have good lights, break lights and ,left and right turn signals. However when connect a trailer to trailer to the factory installed trailer Pig tale, I never get turn signals,all out lights work, just no turn signals, Any thoughts/ Wayne

 

Could be I did not read it right... it was after a long day

If you do not have stop / turn circuit active, 1st thing I would check are the fuses for the trailer tow adapter stop / turn signals.

These are in the BJB ( aka battery junction box, engine compartment fuse panel ) fuses #19 & #20.

Strange that both are blown, but not unheard of.

When you replace the fuses, check with a meter at the 4 pin / 7 pin adapter before plugging in the trailer. use the ground on the trailer tow adapter just for good measure ( to make sure you are getting ground from the trailer tow adapter ).

 

I'm still trying to decipher the symptoms.

Are you saying you have trailer running and brake lamps but no trailer turn signals while the lights ALL work properly on the truck itself? If so, that is an illogical combination that should not be possible with factory wiring. if the fuses that sscully specified are blown, you wouldn't have trailer brake lights.

PS. The brake lights and turn signals are the same two wires. There is no single brake light wire on the factory trailer wiring adapter.

 

Thanks for the information. You are correct , all lights work properly on the truck, when I plug in a trailer , I get all lights,brake lights, running lights, just no turn signals, I see them blinking on the truck, but not on the trailer. Thanks for information and the response.Wayne

 

Thanks for the tip, this is sure a crazy problem, all lights operate correctly on the truck, but when I connect trailer or test light the turn signals don't operate. Thanks again for the response, I will keep cking, Wayne

 

Thanks SScully, this is a crazy problem, I have been out of town a few days, I will try and work on the old ford this weekend. I have to pull a trailer down to Alabama in a week. Thanks again, Wayne

 

Unless you have some weird kind of 5-wire conversion.....

Okay, please pay attention to this.

The turn signals and the brake lamps on the trailer are the SAME THING. The only thing that is different is they're both turned on at the same time for brake lamps but one at a time for turn signals. These bulbs operate in parallel with the truck's lamps with the minor exception that they are individually fused (so a trailer fault won't take out the truck's signals).

 

I have a factory 4 prong plug and an aftermarket 7 prong . 7 Prong is wired in on the forward side of the factory plug with scotch locks...... everything works. Factory 4 prong comes out the back of the factory plug: part of the plug goes to the turn signals, part to the 4 prong plug. Everything works like the 7 prong plug, except the left turn signal. I have left turn signal at the left rear of the truck, I have left rear blinker at the 7 prong plug, I have no left turn signal at the 4 prong plug. I have had the plug apart 12 times in 3 hours . It is clean , I have put dielectric grease in it , I even jumped the wire from the forward side of the plug to the rearward side of the plug , by passing the plug : that caused strange things . Long and the short of it, I cannot figure out why I have no left turn signal at the 4 prong factory plug. I am about ready to cut all the wires and run it straight to the forward side of the plug like the 7 prong trailer plug . There has to be some weirdness in Fords wiring .......any ideas ?

 

May have solved this : It seems there are separate right and left fuses for the factory tow plug....would explain why the 7 prong works fine and the 4 prong does not : one is wired before the plug, one is wired on the rear side of the plug. Fuse 19 and 20, I will check in the morning.