Brake Test

To clarify- the brakes were connected, the Prodigy did tell me that they were, what was NOT connected was the wire that tells the prodigy to put them on. There is no indicator for this other than when the trailer does not stop, well yes there was, the Prodigy did NOT show a voltage increase, just that they were connected. The voltage indicator did activate as soon as I pulled on the lever and the camper brakes did engage. There is not a test for the failure I had of a wire coming off a screw under the dash,(probably not tightened enough at the factory) other than stepping on the brake and having the camper breaks engage. But yes, your test should be adequate.

Every time I start up the truck, as I pull away, I manually engage the TM brakes. I can feel it drag.

This does not guarantee that both brakes are operating, or operating evenly. It only demonstrates that at least one wheel is braking.

From experience, I know what "normal" feels like.

I have the GMC IBC. If the TM plug is not fully inserted into the socket of the truck then when I start up I do not get the message that indicates that the trailer is connected. So I go back and reseat the plug.

I like having the display on the dash where it is easy to see how much power is being fed back to the TM. Under heave braking it will normally read 7. Whatever that means. But as long as I consistently get the same numbers in similar situations then I don't worry too much.

Another reason I am not worried about the brakes on the TM too much is because my truck will have no trouble stopping both the truck and the TM. I tested that once while towing with a 1989 Chevy 3/4 ton Suburban. It was an emergency tow for 40 miles and the Suburban was set up to tow a boat, with only 4 wires. I had no trouble braking.

Originally Posted by PopBeavers

Every time I start up the truck, as I pull away, I manually engage the TM brakes. I can feel it drag.

This does not guarantee that both brakes are operating, or operating evenly. It only demonstrates that at least one wheel is braking.

From experience, I know what "normal" feels like.

Well, that's what I thought too. I was very surprised to discover that only one of my brakes was working. Luckily there were no emergency stops required.

Originally Posted by PopBeavers

...
Another reason I am not worried about the brakes on the TM too much is because my truck will have no trouble stopping both the truck and the TM. I tested that once while towing with a 1989 Chevy 3/4 ton Suburban. It was an emergency tow for 40 miles and the Suburban was set up to tow a boat, with only 4 wires. I had no trouble braking.

When I first picked up the Elkmont, we drove most of the day without trailer brakes (didn't have the Prodigy set properly). No problem braking. But no emergency braking either.

Emergency stops were different. With the old Prodigy controller I would lower the braking voltage when in town getting gas, to stop the jerkiness, and occasionally would forget to increase it when getting back on the highway. Once I forgot and had to hit the brakes hard when somebody cut in front on the highway. It was like the trailer had no brakes. The trailer pushed the truck forward and jackknifed to the side. That wouldn't have happened if the trailer's brakes had been working properly.

IMHO the trailer's brakes are the weakest link, safety-wise, in our trailering travels. The truck with it's built-in brake controller (which auto-adjusts for speed!) and many other braking/trailering safety features is a marvel. By comparison, the trailer brakes are pathetic.

So yes, maybe I'm paranoid about this, but it does come from our own experiences.

Originally Posted by brulaz

... when I pull the emergency brake plug, there's 7.3A on the line. About what you expect for both brakes working. Working both brakes with the pedal should be similar ...

Guess not, because Ford's integrated brake controller adjusts the Voltage and Current to the brakes depending upon the truck's speed. When the truck is just sitting there, all I get when pressing on the brake pedal is ~750mA. Just a tenth of what I get when pulling the Emergency Brake Plug.

And if I install an ammeter in the cab to monitor brake current, the numbers would vary depending upon both speed and brake pedal pressure. Not that useful.

Presumably if one of the brakes was not working, the current at rest would be ~370mA. But I'll have to check that one of these days.

If you use an ohm meter at the trailer plug, between ground and the trailer brake pin, you shoud see 1.6 ohms plus or minus a bit if you have two electrically connected brake drums. If you see 3.2, you only have one brake electrically connected. If you have four brakes, you want to see .8 ohms or so.

You still need to be sure you check stopping power - this won't detect mechanical issues.

Originally Posted by grakin

If you use an ohm meter at the trailer plug, between ground and the trailer brake pin, you shoud see 1.6 ohms plus or minus a bit if you have two electrically connected brake drums. If you see 3.2, you only have one brake electrically connected. If you have four brakes, you want to see .8 ohms or so.

You still need to be sure you check stopping power - this won't detect mechanical issues.

Good point, hadn't thought of that. It will certainly detect a broken wire.

But guess I still prefer checking the current with the brake pedal pushed down. That way the whole line, from pedal to brakes, is checked. Especially after hearing about Clown's problem (above).

And yes, I still often double-check by touching both drums just after pulling over to see if they're warm. If they're not warm, something, possibly mechanical, is wrong. That's how I discovered my broken brake line last time.

You could drive in some sand, mud or gravel. Manually engage the TM brakes and pull forward a few feet. With a bit of luck, and wheel with a working brake will leave a skid mark. Andy wheel that is rolling (no brake) will not.

This will not tell you if the brakes are working well, only that they will lock at a very low speed.