Electric Brake Controller troubleshooting

[dcsobob]

Thought there was a thread for this but cannot find it.

Just bought a new trailer with electric brakes on it. My truck has a brake controller on it and I have pulled trailers in the past with eb's and it worked fine. For whatever reason we could not get the controller to fire the eb's on the new trailer. All other items (brake lights, signals, etc) worked fine.

I was getting no readings on the controller so I replaced it with a new Primus IQ inertia controller. When no trailer is connected i get a "NC" code for not connected. I metered the output of the EB pin on my 7-blade and when the manual slide is used I am getting only 120-130mvDC out of it, vice 8-10vDC. When I hook the trailer up to it, the controller still says "NC". This leads me to think i have a wiring issue now on the truck

If It were a grounding issued, I would think that the other lights and such would not work.

How can I verify that my truck wiring is correct and that my EB pin on the truck does not have a wiring break or that it is working correctly? Why would I show that the trailer is not connected when it is?

Thanks for any help

 

[Diamondpilot]

Thought there was a thread for this but cannot find it.

Just bought a new trailer with electric brakes on it. My truck has a brake controller on it and I have pulled trailers in the past with eb's and it worked fine. For whatever reason we could not get the controller to fire the eb's on the new trailer. All other items (brake lights, signals, etc) worked fine.

I was getting no readings on the controller so I replaced it with a new Primus IQ inertia controller. When no trailer is connected i get a "NC" code for not connected. I metered the output of the EB pin on my 7-blade and when the manual slide is used I am getting only 120-130mvDC out of it, vice 8-10vDC. When I hook the trailer up to it, the controller still says "NC". This leads me to think i have a wiring issue now on the truck

If It were a grounding issued, I would think that the other lights and such would not work.

How can I verify that my truck wiring is correct and that my EB pin on the truck does not have a wiring break or that it is working correctly? Why would I show that the trailer is not connected when it is?

Thanks for any help

Is the plug on the truck a 6 or newer style 7 pin? What plug is on the trailer? Reason I ask is the 7 pin plugs have one way of wiring but for some reason the 6 pin have two different ways and if an 6 to 7 pin adapter is used that adds more issues.

Chris

 

[dcsobob]

Both are 7 pin. I have verified that both truck and trailer are wired to same on the 7 pins

I am using constant hot from truck to power my breakaway box. And ground from truck cone te through trailer plug and is connected to trailer frame.

Hmm. Wonder if I need to make sure beak ground is going straight to truck ground on that pun

 

[Soundguy]

try this.

take one of your controllers back to the trailer. pull yer truck nose up to the trailer.

yer controller has 4 wires right? power and ground.

brake signal

and hot to brakes... which is usually blue.

wire the controller to +/-, use jump cables to ground trailer frame to truck.

use a jumper wire from blue on controller to brake line on trailer 7pin. have the traielr up on jacks. see if the controller sees the trailer. if so. spin a tire then hit the manual control.. should activate the brake on the spinning tire.

if that checks out., check that brake power wire from your truck cab to the rear... might be cut or coroded.

i had a 98 dodge that had the ware harness plug in under dash. but blue wire was bad SOMEWHERE in harness. I added a new blue wire and ran it under the truck and in thru firewall.

was glad i did.. use heavy wire too.

90% of trailer wire problems i see are bad grounds. .. past that. it's the trailer brake wire not seeing the magnets via current loop.