FINALLY! New Trailer Blowing fuses

[SteveRay]

My new trailer seems to be blowing fuses. I had no isses with the other trailer which was a round 6 to flat 4.

The new trailer I have a round 7 adapter down to a flat 5 since the trailer is equiped with disk brakes and I was told the 5th wire is a lockout for the brakes when put in reverse.

When I put the truck in drive.....Bam there goes a fuse.

What do you guys suggest I look at??? I am no electrical guru for sure

 

[wire2]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Placing the gear selector in drive from park blips the reverse. And I expect you have to step on the brake to do so? That's 2 of the trailer circuits.

Rather than experiment with a big box of replacement fuses, I'd test with a 5-10 amp battery charger. Connect the - to the coupler or tongue, then touch the + to the other 4 plug wires, 1 at a time. Brown is running, yellow is left turn/brake, green is right turn/brake, last wire (black or red) is reverse lockout solenoid valve. Don't touch the white wire, is ground.

If one of the connections give a large spark and shows high amps on the charger meter, you've found the wire with a short.

Here's some trailer wiring info; http://www.accessconnect.com/trailer_wiring_diagram.htm

 

[Silvertip]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

The problem is very likely NOT with the trailer but rather the round 7 to flat five adapter. Round 7 wiring on the tow vehicle may not match the round 7 plug on the adapter. This is a common problem.

 

[kenmyfam]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

The problem is very likely NOT with the trailer but rather the round 7 to flat five adapter. Round 7 wiring on the tow vehicle may not match the round 7 plug on the adapter. This is a common problem.

I am with this respopnse. It most likely does not match.

 

[tashasdaddy]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

if you don't know electrics, take it back to the dealer you got it from. they can fix it. they should have tested it.

 

[SteveRay]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

UNfortunately the dealer is over an hour and a half away. I am trying to avoid that if at all possible. Furthermore, it was a broker boat.

What you guys had mentioned about the 7 not being compatible majes sense du to the fact that I never had this problem with the other two boats I towed with the previous adapter. Both were 4 flats hooked up to my 6 round. I think I will try a 6 round to 5 flat and see waht happens.
I am also going to try the troubleshooting you recommended.
Thanks guys.....The timely responses keep me from pulling my hair out

 

[SteveRay]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Placing the gear selector in drive from park blips the reverse. And I expect you have to step on the brake to do so? That's 2 of the trailer circuits.

Exactly.....I was stopped at a rest stop on the Interstate and couldn't put the truck in drive sinec it had blown the fuse and wouldn't recognize that I had my foot on the brake.

 

[tashasdaddy]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

this may shed a little light "http://www.accessconnect.com/trailer_wiring_diagram.htm"

 

[SteveRay]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

After looking at the round adapter I bought...I realized that it is no different tahn the one I had (on the truck end) with the exception of the round pole in the middle. I was under the impression that there were supposed to be 6 flat and a round in the middle.
I have a hunch that this is where my problem is since I check the entire trialer system and everythign is hunky dory.

Ohh yeah I threw out the receipt for the new one...

 

[SteveRay]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Bought a new adapter and having the same problem.....Possibility that the reverse lockout solenoid is bad since nothign blows until I place the truck in reverse

 

[Silvertip]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

You can buy adapters until you are blue in the face and not solve the problem. The problem very likely is that the adapter has incompatible wiring between the truck end and trailer end. You need to get a test light or meter and check which pins on the output (trailer side of the adapter) have which function it. If the functions don't match the trailer connector functions, you will have issues. Plug the adapter into the truck. Turn on the headlights, touch the test light to each pin until you find 12V. Note that on a diagram of the plug. Turn the headlights off and turn on the left turn signal. Do the same test until you find the test light blinking or the meter needle pulsing. Note the pin. Repeat for the right turn. You need to know that the brake lights use the same circuit as the left and right turn signals. Then put the truck in reverse and find the reverse light function. If you don't find it, you now know where the problem is. You then need to turn things on until you find what function that pin supports. You have two choices: 1) change the trailer wiring, or change the truck wiring. I still contend the problem is not with the trailer. Google "truck and trailer connector wiring". There are many diagrams that should help you with this.

 

[SteveRay]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Alright....I did a test since I don't have a meter. Put the truck in D with the ebrake on and hooked up the lights.....Everythign is fine....Put it in P and fuse blows again. So I looked at schematic for the plug and it appears that the lockout is going to a auxillary pole in the center..

I dont know which side to fix

 

[JMRuth72]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

I am an Avionics Tech and deal with electricity and electronics alot. I can tell you from experience that this is one of those jobs that you must have the right tools for the job. I would strongly advise you to go buy or borrow a multimeter. A continuity tester might help, you can check for voltage but not for shorts. You have not said whether or not you have tried this with the just the adapter plugged in to the truck. Pop the adapter into the truck by itself and see if it blows the fuse. If the fuse blows then it is your adapter. If not then it is something in the trailer and that is when you will really need the multimeter. If you narrow it down to the trailer use the wiring diagrams that were mentioned earlier with a multimeter and check between the ground pin and every other pin on the plug. The lighting circuits should show atleast a couple of ohms. It would be easier to give you a idea as to how much if I knew how many lights, what type, and how it is wired. I will tell you that I rewired a friend of mines trailer and his were running a little over 2 ohms per circuit. I am not sure what the reverse lockout should be reading, but I would bet that it is some type of solenoid and the coils usually are around 20 ohms or so. Some higher some lower, but it is a good circuit if is shows some type of resistance. You should NOT show ANY circuits with less that 1 ohm, if you do suspect a short. I say 1 ohm because some meters can't truly read ZERO. Let us know what you find or you can PM me and I will talk you through it. It is not hard, just tedious. Good luck.

 

[Silvertip]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

I repeat -- it doesn't matter what you have on the truck. What passes from the truck through the adapter to the trailer is what matters. You need to identify what you are getting OUT of the five pins on the adapter. If that doesn't match with the five pins on the trailer you need to change one end or the other. Adapters are wired one way only. Unfortunately, the truck connectors may not be wired the same from one manufacturer to another. Test lights are about five bucks at an auto store. Use your battery charger to see what pin is what on the trailer end. Since you had the truck in drive and shifted to Park, you went through reverse to get there. Reverse on the truck is a clue. Or, if you had your foot on the brake when you did the shifting, there could be a problem with the brake AND reverse wiring on the truck connector. Check back in a bit, I'll dig out some wiring diagrams that should help clear this up. In the mean time, buy a test light.

 

[JMRuth72]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

P.S. Silvertip brings up a really good point. If the adapter itself is not shorted that doesn't mean that it isn't still the problem. The output wiring of the adapter MUST match the input wiring of the trailer. If you don't have a continuity tester then a light bulb with 2 wire leads works. With the adapter plugged into the truck and a helper behind the wheel with the engine off. Plug one lead from the light into the ground pin. Plug the other lead from the light into the pin next to it and have helper turn the headlights on/off, push the brakes, etc.. until you see the test light come on. Continue until you have identified all of the pins as to function for lighting. The spare pin will be the reverse lockout that should light the test light when your helper puts the truck in reverse. Of course this last one is why you want to conduct this test with the truck off, parking brake on. I went through and verified my friends truck and adapter wiring before I rewired his trailer and it all works great, but all I had to deal with was lighting. Again let us know what you find and good luck.

 

[wire2]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Alright....I did a test since I don't have a meter. Put the truck in D with the ebrake on and hooked up the lights.....Everythign is fine....Put it in P and fuse blows again. So I looked at schematic for the plug and it appears that the lockout is going to a auxillary pole in the center..

I dont know which side to fix

So the fuse blows when R is on, going from D to P.
Is there 12 v on the center pin, with a good fuse, in R, and the trailer is not plugged in?
With the charger - on the tongue somewhere and touching + to the trailer center pin, do you get a large spark and hi current on the meter? Or just a very small spark and a click from the solenoid?

 

[Silvertip]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Here is what you have. You need a test light to verify that each of 7 pins is functioning as intended. You then plug in the adapter without the trailer connected and test the five pins to make sure each of those five pins has the function indicated in the chart. If the truck is right and five pins are not, you need to change the trailer to match or the truck to match. Your choice. If the five pins on the adapter are correct, THEN the problem is at the trailer.

 

[Wide Open]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

Dude that is an awesome diagram!

 

[Silvertip]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

I forgot to add that since you don't have electric brakes, the electric brake line must NOT feed through the adapter to any of the five pins either.

 

[SteveRay]

Re: New Trailer Blowing fuses

Re: New Trailer Blowing fuses

You guys have been great!!!!!!!
I need a meter and haven't had time to head out today. I think I will borrow one from work or buy one tomorrow.

I'll keep you posted.

THANKS!!!!!