Not getting 12v at the Electric brake pin in the 7pin connector on the truck

[marcusldaniels]

2015 Ram 3500 Tradesman Diesel automatic

Ok long story short and 4 weeks later, I tested the 7 Way connector for the trailer tow and discovered that it was not getting 12 Volts to the lead that is supposed to give 12 Volts when the brake is pressed. This lead is the Electric brake lead. All the other leads, the left stop signal, right stop signal gets 12v when the brake is pressed and the constant lead gets 12 volts without the brake pressed. The electric brake lead is not getting 12 volts when the brake is pressed. Ive checked the two fuses under the hood, Ive pulled the connector off thats connected to the back of the 7 way plug and tested each lead and they do the same thing as if it was plugged in.

Is there a disconnect somewhere that im missing? Somewhere in the brake controller lever thats not connected and making that circuit not work thats to the electric brake? Ive been messing with this thing for 4 weeks and finally figured out that the actuator pump is not gettting the 12 volts it needs to activate the brakes on my trailer. Im at a loss here and I know its probably something simple but Ive changed the brake controller module as a last resort thinking that it may have been the problem but its not. Can someone please help!!

 

[chri5k]

Are you getting any reading? Is it the factory brake controller? Brake controllers don't usually apply the full 12 volts. If they did most trailer brakes would lock up. The factory system is Pulse Width Modulated (PWM). It does not produce a steady voltage rather it pulses with the magnitude, duration and interval of the pulse determined by the brake module. This system provides smoother braking as well as a simulated anti-lock capability. A conventional volt meter can not read the pulses correctly. The system also detects if a trailer is connected so if you don't have one connected it won't even try to apply a PWM signal. You can buy one of the 7-way plugin testers which have a small circuit in them to fool the controller into thinking a trailer is connected and light the test light when brakes are applied. Specialized meters or an oscilloscope would be necessary to actually read the PWM signal.

 

[crash68]

 

[marcusldaniels]

Are you getting any reading? Is it the factory brake controller? Brake controllers don't usually apply the full 12 volts. If they did most trailer brakes would lock up. The factory system is Pulse Width Modulated (PWM). It does not produce a steady voltage rather it pulses with the magnitude, duration and interval of the pulse determined by the brake module. This system provides smoother braking as well as a simulated anti-lock capability. A conventional volt meter can not read the pulses correctly. The system also detects if a trailer is connected so if you don't have one connected it won't even try to apply a PWM signal. You can buy one of the 7-way plugin testers which have a small circuit in them to fool the controller into thinking a trailer is connected and light the test light when brakes are applied. Specialized meters or an oscilloscope would be necessary to actually read the PWM signal.

Ok thats feasible and easy to understand. So it does read or say if anything is connected or not. When its plugged in, it reads that the trailer is connected and when its unplugged, it reads trailer not connected and the pic turns red. So what controls the PWM signal? the Brake control module or the brake controller switch? There must be a disconnect at the switch. Im aware that if one of the two within the system is not connected in some type of way, none of it will work? Im glad you mentioned the PWM because I was ready to go and just put the brake light wire to that lead and I'll surely have 12v when i hit the brake. thanks for mentioning that.........something is going on with that circuit. Oh and no, not getting any reading at all or i think i noticed that it had a .0124 or somthing like that. I was looking for it to jump to 12 v is why I wasnt paying attention to if it gave any kind of reading such as that. So I did change the module out and im going to take a look at the controller switch to see if a connector is not connected back there for whatever reason. Mind you, at one point everything worked. Dont know when or how it stopped working.

 

[chri5k]

I always keep a 7-pin tester under the back seat. Rolled up to a friends place a while back and they had the whole trailer wiring striped from the trailer trying to figure out why the trailer lights and brakes were not working. I popped my tester into the 7-way and nothing. Checked fuses, all OK. Started with the truck wiring harness from the plug back. Found the connector from the harness to the plug in the rear bumper was not fully seated. Pushed in until it locked and voila', lights and brakes.

 

[marcusldaniels]

I always keep a 7-pin tester under the back seat. Rolled up to a friends place a while back and they had the whole trailer wiring striped from the trailer trying to figure out why the trailer lights and brakes were not working. I popped my tester into the 7-way and nothing. Checked fuses, all OK. Started with the truck wiring harness from the plug back. Found the connector from the harness to the plug in the rear bumper was not fully seated. Pushed in until it locked and voila', lights and brakes.

Yes sir, all of the above ive explored! I pulled it out from the back of the truck, it even still has a good coat of grease on it, I tested each pin while it was unhooked from the connector and connected it back and tested again. They all work except the electric brake pin in which is supposed to atleast give something because its operated by the Pulse width module. suppose i have to find that.

 

[chri5k]

A voltmeter may not be enough resistance to trigger the "trailer connected" function of the TBM. Have a friend hold the voltmeter probes on the correct pins while you see if the truck shows a trailer is connected. The step on the brakes. You won't get a solid voltage reading but it may fluctuate around 1v or so. I would get a 7-way plug-in tester from the parts store. Those have a load resistor to make sure the TBM thinks a trailer is connected.

 

[marcusldaniels]

A voltmeter may not be enough resistance to trigger the "trailer connected" function of the TBM. Have a friend hold the voltmeter probes on the correct pins while you see if the truck shows a trailer is connected. The step on the brakes. You won't get a solid voltage reading but it may fluctuate around 1v or so. I would get a 7-way plug-in tester from the parts store. Those have a load resistor to make sure the TBM thinks a trailer is connected.

Ok cool, getting the 7pin tester tomorrow, thanks!

 

[sobrbiker]

Non-electrical hillbilly troubleshoot-plug trailer in, start truck, test probe on e-brake wire on trailer and push brake pedal. Don’t expect full 12v, as said, but you’ll know if voltage is headed to brakes’ electromagnets.

 

[dkbinco]

Hey guys, I'm sure you figured it out by now. I am here for a similar reason, 96 Ram 5.9 and it has a takonsha 2030, I had to replace the 7 blade connectors, I have 12 v. to supply BLK wire, and 12 v. to brake light RED wire when I move the slide or depress the brake pedell, but the red led dosn't lite or do I get any voltage coming out of controller on elec. brake feed BLU wire. I can get an intermittant volt reading of sometimes 7 v. disconnected a couplke in. from controller to feed to trailer. I was told by a couple googles that the problem is in the controller and replace it.
I appreciate any feed back.