Trailer connection 4 pin to 5 pin on truck

My connection on my truck and trailer are both corroded. I think the best solution is to replace both. I have a 5 wire connection on my truck and a 4 pin connector on my trailer. What would you suggest is the best way to replace these?

Also, when replacing these, what is the best way to protect the new splices?

Thanks for your help!

Re: Trailer connection 4 pin to 5 pin on truck

You can get crimp splices that have a heat shrink sleeve. Once you make the splice you just shrink the sleeve and it forms a pretty much water tight seal. I use them and add a little dab of silicone before I shrink the sleeeve.

Re: Trailer connection 4 pin to 5 pin on truck

you have two different systems. will have to buy converter from 5 to 4 or rewire trailer for a 5 pin system. lights and all.
5 pin uses ground, parking, left, right, brake.
4 pin uses ground, parking and the left and right. the truck takes care of the conversion for the brakes on a 4 pin to 4 pin.
just had to do it for a old land rover.

Re: Trailer connection 4 pin to 5 pin on truck

I use bare crimp connectors, then paint on some liquid vinyl "electrical tape" and then use shrink tube. Never failed yet!

You can get the converters at U-Haul or most auto parts stores.

Re: Trailer connection 4 pin to 5 pin on truck

The difference between the two is that on the five pin flat connector the additional pin is for reverse lockout for disc brake trailers. You can leave the wiring as it is and it will plug in just fine. I have used U Haul trailers that are 4 wire and they plug and work just fine in my 5 pin flat.

Gary

Re: Trailer connection 4 pin to 5 pin on truck

That works fine if it is a FLAT 5.

Re: Trailer connection 4 pin to 5 pin on truck

That's interesting because that's exactly what I've found out. If I just plug it in, everything seems to work fine even though there's a different number of pins on the connectors.

I like the ideas of how to protect the splices.

Thanks for all of the help!

Re: Trailer connection 4 pin to 5 pin on truck

gcope63, you got an old man confused. lol So i started looking over the net for some answers and got more confused. When in doubt ask an expert, so i called a budy who sells trailers. There is no standard on the flat 5-pin, the trailer and auto manufactures are still at it last he knew. If you have the yellow turn signals you will have to convert, some auto makers due this in the car/truck others have to buy the aftermarket kits. He said it's simple
READ YOUR OWER'S MANUAL. Got to love the pros. Sorry for the confusion.

Re: Trailer connection 4 pin to 5 pin on truck

My owners manual ('99 Chev Tahoe) says that the 5th wire (blue) is for an auxilary / electric brakes which I don't have. So what I decided to do to try to keep things simple was change the five wire connector on my truck to a four wire connector. I just didn't connect the blue wire.

So then I noticed the other night on my way home that the turn and brake lights work fine but I didn't have any running lights!?!?! Now what?

Thanks.

Re: Trailer connection 4 pin to 5 pin on truck

Well let's start. take your test light and check the power from the truck. one end on the ground pin the other on the power for the marking lights. if that's good go to the steel bumper for a ground. if no light go from bumper to plug pin ground, if it lights you crossed ground and marker pin. if not crossed go back to truck marker power pin. if you have light go to trailer and truck marker pin. if the trailer is hooked up there will be enough ground threw the coupler to light the test light. next is truck marker pin to trailer marker pin. if no light on tester you have broken circuit on trailer. check the first marker light on the trailer with the test light still hooked up to supply power (truck marker pin)and the trailer marker pin. bulb OK? check for a ground at the light. if there is one there the bulb should work. you can use a piece of wire to ground out the ground side of the bulb if there is no ground. if no light, remove the bulb and ground the power side of the bulb plug, the test light should light, if not the power wire/trailer plug is bad to the first marker light or you blew the fuse in the truck. take the tester back to the truck if it lights the truck's fuse is good. if the marker bulb lights, when you ground it out you have a bad ground on the trailer (sinse the brake lights work make sure your good to this point, the ground could be good). if there is a ground at the first marker fix it, if the ground is farther down the line, plug the trailer in and take your tester and go between the first marker light bulb ground side and the trailer to get a good ground. both the bulb and the tester should light again. now look at all the marker lights and find the one that has the ground wire (it's usually a wire from the last marker to the trailer). fix/repair. that will usually fix all the lights, if not you know how to test the markers now one by one. take your time and be careful not to blow the fuse when you go inside of the sockets with the tester/wire. good luck.

Re: Trailer connection 4 pin to 5 pin on truck

Wow! Thank you very much! I'll follow your instructions and report back.