07 M2 parking brake light and low air buzzer issue???

[awayne]

I have a 2007 M2 Freightliner that just started yesterday driving down the road with the brake light on the dash on and the low pressure buzzer on while driving. Everything checks out ok other then the light and buzzer... No issues with low air pressure. At first it was going on and off... on and off. Now it just stays on and buzzes... very annoying.

What do I need to check and is it something that I can check and or replace myself?

I gotta get this fixed ASAP this week since I will be leaving for FL at the end of the week.

Thanks in advance for help.

 

[Slo-Ride]

Short of turning the radio up louder and putting a piece of tape over the light,,your pretty much stuck with getting it fixed.

I just went thru this with my truck,,it turned out to be the AMV located back by the drive axle and up on the frame rails..
While looking up at it,You will see a set of valve blocks with air lines and wires,,,It was the valve located closest to the right side of the truck (the last one in-line).
Fairly cheap to fix even if ya let freightliner do it as I did..Just under $100 for the part if I remember right.Less then 1 hour labor for dealer to do it.

 

[awayne]

I also forgot to mention that I have hydraulic brakes, just the parking brake is air.

Now, I assume the AMV is located in front of the axle, not behind?

If it cost you $100, I'm sure mine will be $200 at my freightliner dealer since it seems everything is more expensive at mine LOL.

One other thing is my indash pioneer screen is saying when I first start up that my parking brake lead wire is not connected correctly and to check it.... Going to find out where this is connected since I am sure its linked to the other issue.

 

[Slo-Ride]

I also forgot to mention that I have hydraulic brakes, just the parking brake is air.

Now, I assume the AMV is located in front of the axle, not behind?

If it cost you $100, I'm sure mine will be $200 at my freightliner dealer since it seems everything is more expensive at mine LOL.

One other thing is my indash pioneer screen is saying when I first start up that my parking brake lead wire is not connected correctly and to check it.... Going to find out where this is connected since I am sure its linked to the other issue.

Well in this case forget everyhing I said
I have no clue with the Hyd brakes??? I wasnt even aware the m-2 used air over hyd brakes..
The AMV is for air management valve, Its a set of air valves maybe 5 or 6 all tied together up on the frame rails.
G/Luck with it. Sorry for the bad info..

 

[layoutshooter]

Those AMU's go out on a regular basis. They are junk. Mine costs $249 plus labor. It goes out every 6 months to a year. I have to have mine checked in a couple of weeks. It is going AGAIN. It has not been six months, the warranty should cover this one.

 

[awayne]

The brakes aren't air assisted hydros, they are just hydro brakes with the parking brake being air assisted.

Now, are the AMU's in the same location as the AMV mentioned above... or are they the samething?

 

[Godwindaniel]

IT is relatively common for the low air warning switch to wear out, it's on the compressor, one wire switch.

 

[Slo-Ride]

AMV,,Air managment valve
AMU,,Air Managment unit,(I think)
Yes should be the same,,Im not sure what freightliner really calls em. I call em AMV's.But keep in mind I all ready said sorry for bad info.

 

[layoutshooter]

AMV,,Air managment valve
AMU,,Air Managment unit,(I think)
Yes should be the same,,Im not sure what freightliner really calls em. I call em AMV's.But keep in mind I all ready said sorry for bad info.

Don't matter what you call 'em as long as you call 'em JUNK!

 

[Slo-Ride]

IT is relatively common for the low air warning switch to wear out, it's on the compressor, one wire switch.

He isnt reporting a low air warning or low air light.

 

[awayne]

Ya, no low air... Just the Brake light on with the buzzer on aswell..... Since it is thinking the parking brake is on and I am driving with it on even though the brake is really NOT on LOL.

 

[awayne]

But I did recently have the air tank on my truck replaced.... I wonder it that would have anything to do with it...

I won't be replying for a bit since I won't be infront of my computer for awhile.... But please continue with the replies and I will reply later today.

Thanks again for the help!!!

 

[Slo-Ride]

Don't matter what you call 'em as long as you call 'em JUNK!

Well here we go back adding wires where wires dont belong or where never needed in the past..
The guy that replaced mine stated they have some sort of resistor embedded in the plastic valve and they don't hold up???
Not sure if he knew what he was talking about but system has been working good since he changed out part.

 

[Slo-Ride]

awayne,
When ya get back to your computer hope this helps,,and don't ask me why I still have this in the truck with me but I do..
Numbers on old valve is..
SWB A12-19777-203
Part # on my invoice is....
NGR/27SWB303R SWITCH-AMU Park. NO PSG
Cost was $53.41
Hope it helps ya.

 

[greg334]

What about this pioneer screen thing?

 

[awayne]

Slo-Ride: Thanks for the above info... I was quoted $75 for the part today from my local freightliner dealer which would have to order it in since they don't stock it.

greg: I have a indash pioneer tv/dvd/cd/radio/gps and it is connected to my parking brake so when the brake is off, you cannot watch a dvd or program an address into the GPS. It is coming up with an error about the lead not being connected properly and that I need to check it.

 

[susie q 52]

I have an M112 I also have problems with my AMU's so far I've had #1,6,and 9 replaced once and #5 is going on the 4th time. MY problem with #5 is I'm driving along w/cruise on and it drops off. Apparently if you were following me my brake light would of flashed which knocked off the cruise. very annoying. this happens quite regularly and I know that #5 is out. Each one takes care of a different part of the braking system. Sometimes shutting cruise off for a hour or so and it will work again for a day or two. It's caused by an air leak in the brake. GOOD LUCK with your problem but the AMU system sucks.

 

[greg334]

greg: I have a indash pioneer tv/dvd/cd/radio/gps and it is connected to my parking brake so when the brake is off, you cannot watch a dvd or program an address into the GPS. It is coming up with an error about the lead not being connected properly and that I need to check it.

That may be your problem. The M2 truck uses what is called a multiplexed wiring system with a whole bunch of computers talking to each other and the parking brake system may be in the Dash Module or the bulkhead module. Hooking it up may have screwed something up with the module and it sees the voltage issue assuming you have low air.

I would unhook the unit the parking brake circuit, put in a switch to turn off the access to the screen and see what happens. If it continues (even with a new switch) you need to get it into a freightliner dealer to be checked out.

 

[awayne]

That may be your problem. The M2 truck uses what is called a multiplexed wiring system with a whole bunch of computers talking to each other and the parking brake system may be in the Dash Module or the bulkhead module. Hooking it up may have screwed something up with the module and it sees the voltage issue assuming you have low air.

I would unhook the unit the parking brake circuit, put in a switch to turn off the access to the screen and see what happens. If it continues (even with a new switch) you need to get it into a freightliner dealer to be checked out.

This was done from the factory (Sportchassis) so I don't think it could have caused this problem especially since I have 188,000 miles on the truck and it just now is causing a problem. But I will check it out. Thanks for the info!

 

[awayne]

Just an update....

I replaced the AMU for the parking brake and it resolved the issue. I did it myself in about 1 hour and could actually do it quicker now that I have done it once. Beats paying Freightliner $100+ to do it.