No Brakes

Brewhedd · 10-28-2018, 10:46 AM

Moving trailer noticed rear brakes on tandem axles were locked, "check trailer brakes" message in truck. After a couple minutes I realized I had pulled the pin on emergency brake module. Put it back in and brakes released. Now the factory brake controller in truck does not "see" any brakes (no message) and I have no brakes. Checked fuses for brake controller, both are good. DC power from battery in TT all good. Tried pulling pin out of module and no sound of brakes engaging. Any ideas? Another fuse somewhere? Modules only good for one use? Have no idea at this point.

Skip12 · 10-28-2018, 12:14 PM

I would try to disconnect battery and reconnect battery to see if that helps.

If that doesn't fix it, I'd be sure the connection to the truck is good. Are the camper running lights on?

Then I'd hit the battery with a multimeter to be sure it's got sufficient charge. Maybe it's good enough to light the camper but not strong enough to engage the brakes.

I've accidentally pulled the pin as well, so I know they're made for reuse.

**Flybob** · 10-28-2018, 12:21 PM

Do a search as this issue has been discussed before. The OEM brake controller will stop working if the break-away pin is pulled while connected to TV. I do not remember the solution.

babock · 10-28-2018, 01:04 PM

Measure the resistance at the 7 pin connector for your brake circuit to ground. They are around 3 ohms per magnet so 4 in parallel would be less than 1 ohm.

Brewhedd · 10-28-2018, 09:16 PM

Quote:

Originally Posted by Flybob

Do a search as this issue has been discussed before. The OEM brake controller will stop working if the break-away pin is pulled while connected to TV. I do not remember the solution.

Thanks to all.

Seems like the brakes magically started working again on one post I found when I did a search.

Surely this would not damage the oem controller as anyone could accidentally pull the pin. I would expect to see a message such as "Check brake controller" if there was a problem. Strange thing is only the rear axle brakes locked up (in dirt). I am going to try hooking the truck up tomorrow to see if it is working again.

Wileykid · 10-29-2018, 08:39 AM

Quote:

Originally Posted by Brewhedd

Thanks to all.

Seems like the brakes magically started working again on one post I found when I did a search.

Surely this would not damage the oem controller as anyone could accidentally pull the pin. I would expect to see a message such as "Check brake controller" if there was a problem. Strange thing is only the rear axle brakes locked up (in dirt). I am going to try hooking the truck up tomorrow to see if it is working again.

The newer Chevy's absolutely freak out when you pull the pin while connected up. And will not reset itself when you put the pin back in. What you have to do is disconnect the trailer plug and put it back in. I think one time I had to shut the truck off and back on also. Got to love the computer system. I like to test the emergency breakaway switch at the beginning of the season, just to make sure.

If the rear brakes are working, and not the front ones, that would be an issue with the trailer, not the truck.

Iwannacamp · 10-29-2018, 08:43 AM

Quote:

Originally Posted by babock

Measure the resistance at the 7 pin connector for your brake circuit to ground. They are around 3 ohms per magnet so 4 in parallel would be less than 1 ohm.

see....I gotta go back to lectric school... cause this puzzles me.

JohnD10 · 10-29-2018, 09:33 AM

On my first outing with my 5'ver I did the same thing...

Unhitched and pulled away and popped the pull-away brake!

I shoved it back in and enjoyed the weekend and when we were leaving I got the same 'check brakes' message!

So I got out and screwed around with it for a few minutes, all the while the truck off.

So, I thought about it for a few minutes, then started the truck and pulled the pull-away brake plug out while the truck was running and then plugged it back in while the truck was still running and it reset itself and the brakes worked fine!

That was 3 1/2 years ago and they are still working great!

Worth a try if you haven't already!

babock · 10-29-2018, 11:06 AM

Quote:

Originally Posted by Iwannacamp

see....I gotta go back to lectric school... cause this puzzles me.

In what way?

Brewhedd · 10-29-2018, 02:57 PM

Quote:

Originally Posted by Wileykid

The newer Chevy's absolutely freak out when you pull the pin while connected up. And will not reset itself when you put the pin back in. What you have to do is disconnect the trailer plug and put it back in. I think one time I had to shut the truck off and back on also. Got to love the computer system. I like to test the emergency breakaway switch at the beginning of the season, just to make sure.

If the rear brakes are working, and not the front ones, that would be an issue with the trailer, not the truck.

Thanks, didn't get to it today. Yeah the rear brakes being the only ones that locked is puzzling. I will be checking that out. I guess it's possible they never worked. If that's the case I would think the tech that repacked my bearings would have noticed.

Wileykid · 10-29-2018, 09:36 PM

Quote:

Originally Posted by Brewhedd

Thanks, didn't get to it today. Yeah the rear brakes being the only ones that locked is puzzling. I will be checking that out. I guess it's possible they never worked. If that's the case I would think the tech that repacked my bearings would have noticed.

No way he would have known, unless there was something obvious. The only way to check is by applying the brakes.

I would check the wiring. The connections, especially behind the backing plate on the wheels get severed or never connected properly.

Iwannacamp · 10-29-2018, 11:36 PM

Quote:

Originally Posted by babock

In what way?

3 x 4 = 12 I'm sure it's because of parallel as apposed to series. Series of course would drop the voltage. I am still unclear how the resistance gets from 3 to 1. IE I need lectric school.

babock · 10-30-2018, 12:41 AM

Quote:

Originally Posted by Iwannacamp

3 x 4 = 12 I'm sure it's because of parallel as apposed to series. Series of course would drop the voltage. I am still unclear how the resistance gets from 3 to 1. IE I need lectric school.

If you put resistors in parallel, you create less resistance.

https://www.electronics-tutorials.ws...tor/res_4.html

1/Rt = 1/3 + 1/3 + 1/3 + 1/3 = 4/3

Invert to get new total

New resistance = 3/4 ohm

Brewhedd · 10-30-2018, 08:35 AM

Quote:

Originally Posted by Wileykid

No way he would have known, unless there was something obvious.

I was thinking the complete lack of brake dust and new looking shoes would be a tip off.

5picker · 10-30-2018, 08:50 AM

Quote:

Originally Posted by Brewhedd

Thanks to all.

Seems like the brakes magically started working again on one post I found when I did a search.

Surely this would not damage the oem controller as anyone could accidentally pull the pin. I would expect to see a message such as "Check brake controller" if there was a problem. Strange thing is only the rear axle brakes locked up (in dirt). I am going to try hooking the truck up tomorrow to see if it is working again.

Don't jump to conclusions you have brake issues just because the rears locked in dirt but the fronts didn't. Especially if this was the first application of the day.

Brake drums/rotors and brake components can oxidize setting over night. More so in wet weather or high humidity conditions. That oxidation (rust) can make each brake location act differently.

Until you've used the brakes 3-4 times, burnishing the components, the brakes at each axle location can perform drastically different.

I'm often amazed at how many folks I see heading out of a campground in the morning doing a brake test within a few feet of their campsite, wheels sliding and you can see them in there adjusting their gain control and trying it again. Oh boy...

JohnD10 · 10-30-2018, 09:19 AM

I still like to back up to adjust the brakes every so often...

Seems to work for me!

But in this day and age where almost all RV'ers are so afraid to back up and demand pull-thru sites...

Maybe that is the problem!

Maybe modern brakes don't adjust that way...

I don't know...

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