Installed new oem trailer brake controller, no luck

[RamDontFailMeNow]

I was all excited when I installed my own oem trailer brake controller and had the dealer enable it in the computer. Everything appears to present and working in the dash computer / menus.

Problem is, the trailer brakes didn't work.

Testing the plug at bumper, the brake pin gives constant .9 to 1 volt and this does not change whether brake is fully depressed or untouched.

If I unplug the brake controller the brake pin reads zero volts

I checked the harness and looked good. Checked all fuses with tow in the name and looked good.

Got replacement overnighted with warranty and it does the same.

What now?

 

[jvbuttex]

hmmmm maybe bad controller... mine worked, i flashed myself with ALFA... if you have some voltage with the controller, and NO voltage w/o controller, sounds like controller issue.

 

[RamDontFailMeNow]

hmmmm maybe bad controller... mine worked, i flashed myself with ALFA... if you have some voltage with the controller, and NO voltage w/o controller, sounds like controller issue.

Could be but I already tried a second new controller.

 

[RamDontFailMeNow]

hmmmm maybe bad controller... mine worked, i flashed myself with ALFA... if you have some voltage with the controller, and NO voltage w/o controller, sounds like controller issue.

Interesting, hadn't heard of alpha, I have bluedriver but apparently that doesn't allow any programming, that I know of.

Did you use alpha obd with obdlink mx or mx+ or something else?

 

[crash68]

I can't remember if the fuses for the brake circuit is marked with trailer tow but are both of these fuses good?
F11 J Case 30 amp Brake Lever
F87 ATR 10 amp ITBM module
Also if I'm not mistaken, you can't just use a volt meter to check the output of the brake controller, it needs to have some sort of a load on it.
I don't think your Bluedriver will link with the AlfaOBD app to make the changes. The MX or MX+ is the recommended OBD dongle.

 

[BossHogg]

Crash is right, the OEM and most pulse width modulated brake controllers only provide a braking signal if a load is present on the trailer brake line. Hook up to a trailer with electric brakes (inductive load) and then measure the output. Keep in mind, measuring PWM signal is tricky using a voltmeter. They typically will read a lower voltage depending on their sampling rate.

 

[jvbuttex]

Interesting, hadn't heard of alpha, I have bluedriver but apparently that doesn't allow any programming, that I know of.

Did you use alpha obd with obdlink mx or mx+ or something else?

yes alpha obd... not programming, only enabling of the feature in the computer.

Crash is right, the OEM and most pulse width modulated brake controllers only provide a braking signal if a load is present on the trailer brake line. Hook up to a trailer with electric brakes (inductive load) and then measure the output. Keep in mind, measuring PWM signal is tricky using a voltmeter. They typically will read a lower voltage depending on their sampling rate.

would measuring voltage at the braking axle tell you if its applied? I cant imagine the truck knowing if its moving or not. should apply voltage when the pedal or lever is applied.

 

[RamDontFailMeNow]

Well, I feel stupid. I checked more fuses and found nothing, so I got to thinking about pulse wave modulation like you guys were talking about, and the fact that I might not get a read with a multimeter without any load on the brakes, or a trailer detected.

I decided to go for another test drive and, sure enough, they work great. The trailer brakes are strong, I backed it it off to about 7.

When I first tested it I was cruising around twenty and squeezed the manual brake and felt no effect. It could be that since I had been playing with the gain levels, I had it set to 0 or 1 at that time.

https://www.amazon.com/gp/aw/d/B073FJ5NVL/ref=ox_sc_act_image_1?smid=A1VLPNTGGRFAR6&psc=1

I recommend picking up one of these to get an easy true reading of trailer brake strength, almost bought one till I found my brakes were working fine.

Thanks all.

 

[jvbuttex]

Glad you figured it out.

nice tool... good to know they make them.

 

[crash68]

I decided to go for another test drive and, sure enough, they work great. The trailer brakes are strong, I backed it it off to about 7.

When I first tested it I was cruising around twenty and squeezed the manual brake and felt no effect. It could be that since I had been playing with the gain levels, I had it set to 0 or 1 at that time.

https://www.amazon.com/gp/aw/d/B073FJ5NVL/ref=ox_sc_act_image_1?smid=A1VLPNTGGRFAR6&psc=1

I recommend picking up one of these to get an easy true reading of trailer brake strength, almost bought one till I found my brakes were working fine.

Something to keep in mind with the ITBM, vehicle speed is used as part of the calculation for how much to apply the trailer brakes.

 

[BossHogg]

would measuring voltage at the braking axle tell you if its applied? I cant imagine the truck knowing if its moving or not. should apply voltage when the pedal or lever is applied.

While I've never seen a technical discussion on how the ITBM functions from any credible source, I have observed its behaviors from towing. I pull a 4,500-pound boat with hydraulic surge brakes up to a 16-foot dump and a 40 foot Montana fiver, both at 15K pounds and better.

As Crashed mentioned, there is a travel speed, once the vehicle falls below 25 MPH, the braking level from the ITBM is applied differently than when traveling at higher speeds.

The ITBM knows how much you are towing, I know this by the amount of exhaust braking that is applied. When approaching a stop, I simply rest my foot on the brake pedal and the exhaust brake will get to work, applying braking horsepower based in part, on tow weight. Adding brake pedal force increases exhaust braking effort but also electric trailer braking. Remember, the ITBM is a proportional braking system, it provides the trailer in tow with the braking signal needed to slow and stop the trailer so the tow vehicle isn't.

The best way to measure ITBM braking signal is using an oscilloscope but it's is not a common instrument folks have in the toolbox so an amp meter, clamp style, is best since you do not need to interrupt the circuit. Make sure the clamp meter is rated to measure DC and don't try to use some inexpensive meter because you will not get accurate information. If you are poor like me, a Klein Tools CL800 clamp meter for around $130 will do. Rich folks go the $400 dollar route and buy Fluke. Some meters have the ability to measure time periods (Fluke again), as the electric braking increases, so will the period of on-time increase.