Community Forums

smlranger · 04-08-2015, 07:39 PM

I installed the AF1 on my 2014 F150 in January and just finally had time to use the coach for a spur of the moment trip today. I could not get the AF1 to depress the brake pedal. I've checked all the obvious things such as the fuse, all wiring, the air line from the coach to the truck, air line connection at the cylinder that pulls on the brake pedal. In fact, if I pull the break away switch plug, the AF1 pulls the brake pedal down hard as expected. That would suggest the unit is getting air from the coach to fill the little reservoir.

I would suspect some issue with the air supply from the coach but I also have an AF1 on my CRV and towed it about one month ago and it worked fine.

I am wondering if there might be some problem internal to the control box. Any suggestions are appreciated.

Jim_L · 04-08-2015, 07:58 PM

I had a similar experience. Installed the unit on my CRV and just this week, finally installed the coach portion. I couldn't get the brake pedal to depress and immediately worried that I hooked things up wrong. I called SMI to trouble shoot and the process of troubleshooting included unhooking lines beginning at the hitch, then at the AF1 unit itself. It was determined that the unit was installed in the coach and the CRV correctly and then I found that the line coming out of the AF1 box (I believe it was the red terminal) had very little pressure. SMI concluded that something was wrong inside the box and requested that I send it to them. Yesterday, they called to say they found the issue, fixed it and was sending it back. It appears that one of the hoses inside the box somehow disconnected.

I would suggest that you troubleshoot similarly and if necessary, unscrew the lid and take a look inside for a disconnected hose. Sure sounds like the same issue to me and it can't hurt.

dpinvidic · 04-08-2015, 08:08 PM

Do you have a helper to apply coach brakes while you check the toad?
Two things to check. Does the AF1 generate vacuum for the toad brake system?
The air line connectors have a push - to - release color, so you can remove each line to check that you get pressure or vacuum.
There is a venturi vacuum device which generates t he vacuum, you should hear the hiss when Coach brakes are applied.

Darn, it is such a simple system. +1 on removing the lid and checking connections. Pretty simple inside.
could also connect the air line to the CRV to confirm coach side is good.

Dan

Jim_L · 04-08-2015, 08:19 PM

Quote:

Originally Posted by dpinvidic

Do you have a helper to apply coach brakes while you check the toad?
Two things to check. Does the AF1 generate vacuum for the toad brake system?
The air line connectors have a push - to - release color, so you can remove each line to check that you get pressure or vacuum.
There is a venturi vacuum device which generates t he vacuum, you should hear the hiss when Coach brakes are applied.

Darn, it is such a simple system. +1 on removing the lid and checking connections. Pretty simple inside.
could also connect the air line to the CRV to confirm coach side is good.

Dan

There should be pressure at all lines. If you disconnect the line at the hitch, there will be pressure as soon as someone steps on the brake. Hook that one back up and go to the blue one at the box...same thing...should be pressure. Then the red one on the box. They unhook the line attached to the cylinder and check to see that there is pressure going to the cylinder. One thing that SMI mentioned and I failed to mention was to ensure there are no kinks or obstructions between the blue line and the cylinder on the brake pedal.

smlranger · 04-09-2015, 05:25 AM

There are no kinks in any of the air lines. We drove the first leg of our trip and are visiting family out of town so don't have the CRV with us. We are towing the F150 with a golf car in the bed so I need toad brakes. Sending the unit back to AF1 and waiting days for return is not an option. If I call them and they want me to take the box apart so they can talk me thru a fix, I will do that.

I am sure the air lines/system are all intact since the unit sets the brakes on the toad when you pull the breakaway switch plug. It could only do that if the box has been 'charged' with air from the coach.

Jim_L · 04-09-2015, 06:51 AM

I don't think the box is sealed. I still think it would be worth a look. There are several air connections inside the box. I understand what you are saying and running out of ideas.

smlranger · 04-09-2015, 06:22 PM

Update: Issue Resolved

Talked to SMI and they determined that I had their newest version of the AF1 that needs a special adaptation to my coach connections which are configured for the older version (my other AF1 is vintage 2007). My CRV coach-to-toad connection is the single air line plus a 4 wire flat plug. The new AF1 coach-to-toad connection is the single air line only. For my new AF1 to talk to my coach, I need to add a 4 wire flat plug to the truck; ground to truck frame, tie yellow and brown together, and green to the wire that feeds the LED indicator on the dash of my coach. Easy enough.

Dutch Star Don · 04-10-2015, 10:37 PM

I had the old SMI Air Force One with the 4 wire plug. The old style also taps into a brake can and is frowned upon by DOT and Freightliner (my new coach). It hurt to buy another SMI unit, but I really like the new module that is installed on the coach and the elimination of the 4 wire plug. Plus the air tank on the towed has been eliminated. I tested it yesterday and it seems the new unit is more sensitive. I have a light on the dash that illuminates when I step on the brakes. It seems to come on a little sooner.

I did my own install and the new coach module was a lot more work, but a nicer/safer system. I had to weld up a bracket to mount the valve and tank.

smlranger · 04-11-2015, 05:17 AM

Quote:

Originally Posted by Dutch Star Don

I had the old SMI Air Force One with the 4 wire plug. The old style also taps into a brake can and is frowned upon by DOT and Freightliner (my new coach). It hurt to buy another SMI unit, but I really like the new module that is installed on the coach and the elimination of the 4 wire plug. Plus the air tank on the towed has been eliminated. I tested it yesterday and it seems the new unit is more sensitive. I have a light on the dash that illuminates when I step on the brakes. It seems to come on a little sooner.

I did my own install and the new coach module was a lot more work, but a nicer/safer system. I had to weld up a bracket to mount the valve and tank.

Don, when I got the Allure and the dealer moved the old AF1 hardware from my Journey to the Allure, they installed the new coach module. However, I still have to use the 4 wire set up since I tow both the CRV with the older version AF1 and the F150 with the newer box. Now that I know the mod I had to make to my F150 install, I should be good to go.

Dutch Star Don · 04-11-2015, 08:50 PM

I was going to buy just the new module, but they wanted $400.00. PPL had the whole system for $985 on sale. I decided they made enough changes on both units that I would just buy a new one. Now I have spare parts.....

They also added a backflow preventer to the vacuum hose that goes to the power booster. So now there are two. in the system.