Brake controller problem

[JR]

Upon hooking up my trailer I get the "trailer not connected" message. Every single marker light, stop, and turn signal works as should....but no trailer brakes. Manual gain does not work either. Probing the bottom two pins on the truck side (brake and ground) I got nothing. The only fuse I can find in the pdc that I can see relates to my problem is F11 marked "ITBM/trailer tow brake". It ohmed out ok but I swapped it with another to make sure...no difference. I'm out of ideas and need to make this thing work. Headed west Virginia this weekend and I really need brakes.

Thanks as always

On edit, brakes worked two days ago when I unhooked the trailer. Went to hook up earlier and now I've got zero brakes. As mentioned everything else works as it should.

 

[B.G. Smith]

The "no trailer connected is for the brake power only, not the lights. You won't get anyreading at the receptacle in rear if the brake controller is not activated. I believe the trailer brake power comes through a relay. My guess is your controller is defective. bg

 

[mwilson]

I have no experience with the integrated brake units BUT if no helpful ideas come along in the next few minutes I would give it the old total reboot by unhooking the battery feed to the PDM for about 5 minutes....cheap and easy.....

Mike...

 

[JR]

The "no trailer connected is for the brake power only, not the lights. You won't get anyreading at the receptacle in rear if the brake controller is not activated. I believe the trailer brake power comes through a relay. My guess is your controller is defective. bg

Should I not get voltage at the truck side plug with the brake pedal applied?

I really hope it's not fried... everything worked peachy the other day. Crappy timing rearing its ugly head again!

 

[jgillott]

Is it possible to wire in an aftermarket controller if necessary to get you through the weekend?

 

[mwilson]

Has the truck been in the salt?? Green gooey wire somewhere underneath where some moron poked a hole in it with a test light???

Factory connector tight to the backside of the trailer connector??

 

[JR]

Is it possible to wire in an aftermarket controller if necessary to get you through the weekend?

This is above my pay grade and something I'd have to ask the professionals....I did keep my maxbrake out of my 98...it's looking really good about now.

 

[JR]

Has the truck been in the salt?? Green gooey wire somewhere underneath where some moron poked a hole in it with a test light???

Factory connector tight to the backside of the trailer connector??

This was my thought and something I checked, everything looks good and clean. I am pretty sure this truck was never really used to tow, the paint was still in the receiver. I've worn it down more in two weeks than the PO did in almost 3 years.

Here's where it gets weird....the trailer just connected. I am so stumped as to how or why, almost seems like a bad ground but I don't see how. I hauled this thing almost 30 miles earlier today (with no brakes). The marker lights are easily visible from my mirrors so I turned on the lights and watched for any flickering.....thinking bad ground....no flickering what so ever. So I'm totally stumped. Something still not quite right as the brakes aren't what they should be. I can barely lock them up in gravel with the manual gain which they normally would do without hesitation. I set the settings to "heavy trailer" and have the gain turned up. (14k gvw trailer).

 

[mwilson]

There was a thread a while back regarding that with the factory. Not the total lack of brakes that you first had but the fact that you could not force the controller to apply the trailer brakes hard by hand...let me see if I can find it...

 

[jgillott]

Is this the one you were looking for?

https://www.turbodieselregister.com...grated-Brake-Controller?p=2353923#post2353923


Basically removed the factory controller, cleaned the contacts and reinstalled if I am reading correctly.

 

[Thump]

I thought I recalled a thread about the truck not recognizing the trailer (brakes) if connected prior to starting or something, too. Was a PCM flash to fix it.

 

[LandShark]

JR:
I've had some similar problems that I think were fixed by replacing the axle brake wiring with double insulated marine (tinned) 12ga wire. I say 'think' because the problem was very intermittent. I did this fix in the middle of a 9,000 mile trip last winter and the return trip had zero issues. BTW: the axles and brakes were new.

A few things I learned:
The system will tell you the brakes are disconnected - but only if they are connected. When it says 'disconnected' you get zero brakes. So the system knows that the trailer is plugged in, but doesn't like what it sees and will not allow the brakes to activate.
Brake System sends a micro pulse about twice a second, on the brake line, which is how it knows if brakes are connected. A small led light in the brake circuit will show this. I suspect that anything except a perfect connection will not allow the computer to see the micro pulse and will set the disconnect message and turn of the brakes.

My guess is that the old style controllers can 'burn through' a dirty or poor connection and our integrated controllers must have perfect connections.

 

[LFrachtmonroe]

JR:
I've had some similar problems that I think were fixed by replacing the axle brake wiring with double insulated marine (tinned) 12ga wire. I say 'think' because the problem was very intermittent. I did this fix in the middle of a 9,000 mile trip last winter and the return trip had zero issues. BTW: the axles and brakes were new.

A few things I learned:
The system will tell you the brakes are disconnected - but only if they are connected. When it says 'disconnected' you get zero brakes. So the system knows that the trailer is plugged in, but doesn't like what it sees and will not allow the brakes to activate.
Brake System sends a micro pulse about twice a second, on the brake line, which is how it knows if brakes are connected. A small led light in the brake circuit will show this. I suspect that anything except a perfect connection will not allow the computer to see the micro pulse and will set the disconnect message and turn of the brakes.

My guess is that the old style controllers can 'burn through' a dirty or poor connection and our integrated controllers must have perfect connections.

Spot on. My buddies trailer had one working brake. My truck showed disconnected. His gmc worked fine. My old truck worked fine, but again only 1 of the 4 brakes were hooked up. Because it is so finniky it shows a complete shutdown instead of powering through the bad brakes. I was not a fan. I had to replace wiring to get one complete axle before I could get my controller to give any braking.

 

[JR]

OK! I think you may be on to something here! I did notice the passenger side brakes weren't locking up at all on gravel last night while the driver's side is....also the last few times I hauled this trailer with my 98 I did have to raise the gain more than normal to get satisfactory braking. So I will definitely look at the pass side brakes asap. I tried to get the day off but there's too much going on so hopefully I can get home at a decent time tonight to look into this some more. We aren't leaving until Sunday so worst case scenario I'll have to get up early in the am...boy do I hate not being prepared.
I will definitely update you all with my findings....thank you all for the suggestions.

 

[NIsaacs]

Activate your brake-away switch and see if your brakes work. If they do, that will eliminate your power side of the brake wiring and point to your ground.

Nick

 

[Ram4Sam]

I thought I recalled a thread about the truck not recognizing the trailer (brakes) if connected prior to starting or something, too. Was a PCM flash to fix it.

TSB#08 082 16

Sam

 

[mwilson]

OK! I think you may be on to something here! I did notice the passenger side brakes weren't locking up at all on gravel last night while the driver's side is....also the last few times I hauled this trailer with my 98 I did have to raise the gain more than normal to get satisfactory braking. So I will definitely look at the pass side brakes asap. I tried to get the day off but there's too much going on so hopefully I can get home at a decent time tonight to look into this some more. We aren't leaving until Sunday so worst case scenario I'll have to get up early in the am...boy do I hate not being prepared.
I will definitely update you all with my findings....thank you all for the suggestions.

Sorry JR, had to abandon you last night. I'll be glad when this week is over...

So a possible quick and dirty check if you suspect wires rubbed through in the axle tubes would be to unhook the wires to one axle at a time and see if that makes the controller happy...should just be a POS ScotchLock where the frame wires hook to the axle wires....if you isolate the problem axle then unhook the next ScotchLock that feeds the wires going to the brake running through the axle tube.

I've had that issue in the past and the wires within the axle tube are not much the day the axle is made. I replaced mine with 14/2 conductor with the heavy gray casing.

Another though before you do anything else is find someone else's trailer (with working brakes) to plug into for a minute just to verify proper operation of the truck's controller.

 

[LandShark]

Activate your brake-away switch and see if your brakes work. If they do, that will eliminate your power side of the brake wiring and point to your ground.

Nick

This will only tell you if you have a major problem; broken wires or bad ground or just no connection. Tripping the brake-away switch puts full battery voltage (12.7v DC) into the brake circuit. Brake controllers ramp up the voltage from about 5v to maybe 11 or 12v. 5v is less likely to make it through a poor connection than 12v.

 

[NIsaacs]

This will only tell you if you have a major problem; broken wires or bad ground or just no connection. Tripping the brake-away switch puts full battery voltage (12.7v DC) into the brake circuit. Brake controllers ramp up the voltage from about 5v to maybe 11 or 12v. 5v is less likely to make it through a poor connection than 12v.

I am not sure what your point is, anytime your trailer brakes don't work, that is a major problem and can be anything anywhere. Any trouble shooting is a methodical process of elimination. If the brakes work with the emergency system, that means the secondary circuit is probably okay, such as axle/backing plate wiring, magnets and even brake adjustment. Now I would look upstream for failures. Since the brake-away system has it's own battery the primary circuit is independent of the truck.

If they don't work, then now you can start looking at the axles. The plug is a major source of issues. Since the left side seems to work some but not the right that indicates a bad splice somewhere close to the left brakes, the farther away you get the less you have.

The new modular sealed wiring harness that trailers are using now are sealed so well you can't hardly get to any connections since there is no junction block.

Nick

 

[JR]

It ended up being some faulty wiring/connections supplying the pass side brakes. Pulled new heavier wire through the axle, soldered and shrink tubed all connections and both sides are working equally AND better than they have in a while. The pass side did work but very poorly, and that was on an empty trailer no less. It took hooking to a different truck with a sensitive controller to show the resistance in the wiring.... thank you to Landshark for pointing me in the right direction. I was too quick to blame the truck. And thanks to all for the suggestions! Each and every one is greatly appreciated.