915-A1 Help!

[Camo]

I have a AM General 915-A1 I'm working on and what I'm having a problem with is the rear brake lights are staying on until I bleed the air completely and then they go out. I have replaced the headlight switch, replaced blackout switch and ohmed out all the relays by the glove box. Can someone give me some info where I need to go next and figure out Y these brake lights stay on. If I leave the blackout switch in blackout position it has a open relay and drains the batteries within a day and if I leave it in the normal position the rear brake lights stay on until the air is completely drained. And all this does this with the key off. I'm very unfamiliar with these machines and just don't know where and what to check, please help!

 

[Bighurt]

Is your Johnson bar pulled, even a little and the switch is activated to illuminate the lights.

 

[Camo]

What and where is the Johnson bar?

 

[Bighurt]

It's your hand brake on the steering column.

 

[doghead]

An appropriate thread title would be appreciated. ( it might even help you or others in the future).

 

[MWMULES]

Camo , Help! in title should be reserved to, Help! I am broke down on...... or Help river is rising and I am stuck. A better title "Can't get my 915 brake lights to go off"

 

[Camo]

Well no offense guys but its not like I've been on this sight forever and know what or how or where I'm suppose to post on here. I did my best and thought I found the right place to ask for help. I mean I'm new here and you sure don't make a person fill very welcome. Give me a break I just needed some insight from some of the folks on here. I mean you guys on here seem to know your stuff inside and out and all I'm trying to do is fix a truck for a local fire dept.

 

[doghead]

And we are trying to help you. (and the other 40000 members)

What was said that was unwelcoming?

 

[Camo]

Well thanks.

 

[doghead]

I would try changing the brake switch. It sounds like it is simply sticking on.

 

[Camo]

Where do I find the brake switch?

 

[doghead]

I think it's on the brake pedal valve.

Troubleshooting the brake lights is covered in, TM 9-2320-283-20-1.

 

[doghead]

You can download the manuals from here, http://www.jatonkam35s.com/jatonkaM915seriesTMdownloadpage.htm

 

[Ferroequinologist]

If bleeding the air completely causes them to go out, then the switch cannot be stuck. If you start the truck, don't touch the brake pedal at all, and as soon as air comes up the lights come on, you have either an internal leak in the treadle valve (the big brake valve on the firewall) or the hand brake lever is on, or leaking by. If they only come on and stay on after you have applied the brakes once or twice, then I would suspect a slow or sticky brake light switch, or a problem with the air bleeding off the brake circuit. Does it seem like the brakes drag if you drive it when the lights are still on?

Does it do it with a trailer on or off? or does it not matter?

 

[73m819]

I am guessing the hand brake control valve is not FULLY OFF

 

[Ferroequinologist]

Me too, or that it is leaking by. One way to tell is to have the service line right behind the cab, just sitting on the deck. With air built up, if the valve is leaking, you will feel/hear air coming from that gladhand. There are no shut off valves on the 915's for the trailer lines, just the ones on the back by the pintle.

 

[73m819]

Me too, or that it is leaking by. One way to tell is to have the service line right behind the cab, just sitting on the deck. With air built up, if the valve is leaking, you will feel/hear air coming from that gladhand. There are no shut off valves on the 915's for the trailer lines, just the ones on the back by the pintle.

Have to have the protection valves RELEASED for this to happen, the protection valves replace the shut off valves

 

[Ferroequinologist]

Ah, yep, forgot about that too. Been awhile since I drove it! Ron is right.