Weak brakes & battery box confusion.

[oliver1555]

Deleted

 

[ddbackhoe]

The black and white wire (duplex) circled in green goes to your brakes. Both axles or just one? Put an ammeter in series with the blue and black wire circled in red and see how many amps it pulls 7 (2) -16 (4) with the truck brake applied. Put an ohmmeter across the black and white (disconnect one side) and you should see about 16 ohms of resistance. A fairly quick test is jack up one side spin the wheels and hit the brake. See if the tires stop, while holding the brake, does

the tire turn easily by hand?

I’m guessing that your Ram isnt the issue. Does it work with a different trailer?

 

[Hay Dude]

The black and white wire (duplex) circled in green goes to your brakes. Both axles or just one? Put an ammeter in series with the blue and black wire circled in red and see how many amps it pulls 7 (2) -16 (4) with the truck brake applied. Put an ohmmeter across the black and white (disconnect one side) and you should see about 16 ohms of resistance. A fairly quick test is jack up one side spin the wheels and hit the brake. See if the tires stop, while holding the brake, does View attachment 807645the tire turn easily by hand?

I’m guessing that your Ram isnt the issue. Does it work with a different trailer?

On my big GN trailer, the brakes work perfectly. It’s something on the smaller trailer itself.

The small trailer has brakes on both axles.

The brakes do work, but they are weak, like maybe 30% of what they should be.

 

[ddbackhoe]

On my big GN trailer, the brakes work perfectly. It’s something on the smaller trailer itself.

The small trailer has brakes on both axles.

The brakes do work, but they are weak, like maybe 30% of what they should be.

Great, half the battle. Now all we have to do is follow the black and white wiring trail, probably a bad splice wherever they jumped in both axles ( splices usually on drivers side of trailer) or bad ground point on one of the 2 wires

 

[Hay Dude]

Thanks. I am going to unload the mowers and try to start looking today. I had a feeling it would be a bad ground or wire splice.

 

[ddbackhoe]

Thanks. I am going to unload the mowers and try to start looking today. I had a feeling it would be a bad ground or wire splice.

I dont see a dedicated ground wire from trailer frame to truck so where are the lights and brakes grounded? Hate when they drive in a self tapper and call it good.

 

[Hay Dude]

I dont see a dedicated ground wire from trailer frame to truck so where are the lights and brakes grounded? Hate when they drive in a self tapper and call it good.

Wouldn’t that be in the 7-pin plug?
They do have a self tapper on the trailer itself

 

[John0829]

The 7 pin connector does have the ground. On the trailer if I find a self tapper I will remove it to replace it with bolt, nut and star washer.

 

[Hay Dude]

I will try that first.

 

[dieselscout80]

Over on the HD Ram forum they say one of the types of 7 wire trailer plugs is incorrect.

In the attached picture the correct version is on the right side.