'07 M2 Gremlins

[truckblue]

My 2007 M2 Business Class has a couple of electrical quirks. One is when I turn on my turn signal, my wipers come on and take a couple swipes then turn off. The other is my headlight randomly goes off, then comes back on, usually after a few seconds. I thought they might be common problems for this model...thanks for any help.

 

[stamp11127]

Wouldn't happen to have a wiring diagram laying around would you? I did some searching on the net and found this to start with.

https://secure.freightliner.com/accessfreightliner/docs/public/m2bodybuilder/wiring/010-grounding%20%28280%20module%29/g06-38574.pdf

Check the grounds first for high resistance/voltage drop on the headlight and wiper circuits.

 

[greg334]

This is a multiplexed truck, I would get it into a shop that has the right tools to talk to the different modules. It maybe the one in the dash but that is a guess.

 

[davekc]

Another brilliant offering from Freightliner. You have a multi-function turn signal switch. The contacts have worn and it likely needs replaced. You can take the assembly apart and apply dielectric grease at the contacts, but that is a temporary fix. Very common problem on Freightliner and Sterlings from 05 and up.
That switch controls brights, wipers, turn signals ect.

 

[greg334]

Oh I forgot about that, who was it that discovered that and wrote about it, you Dave?

 

[Doggie Daddy]

My 2007 M2 Business Class has a couple of electrical quirks. One is when I turn on my turn signal, my wipers come on and take a couple swipes then turn off. The other is my headlight randomly goes off, then comes back on, usually after a few seconds. I thought they might be common problems for this model...thanks for any help.

Yes these are problems common on the M2, our '07 M2 does both of these things.

But as Dave said pulling the electrical plug on the turn signal stalk and cleaning it with contact cleaner and reapplying dielectric grease will solve that problem. Did mine in about 5 minutes.

Now as far as the headlight problem, I have yet to cure that problem, and it has done it since the truck was new. The headlight is not actually going completely off,as we have had the headlight burn completely out and there is a noticeable difference. Got to be a ground problem, but where??

 

[layoutshooter]

Our headlights will "flicker" for less than a second. No shop has ever found the problem. This is my first and last M2. Far too many of these little "quirks" and Freightliner can't seem to fix any of them. Have you had a problem with Air management units yet? I have had to replace the same one so many times I would have to get out the books to count it up. Freightliner KNOWS the unit is bad and does NOTHING to fix it.

 

[davekc]

That headlight issue could be right from the turn signal switch. It is not getting a clean disconnect at the contact. If that has been replaced, check the wires going to the bulk head module. If they look good, disconnect and have the module tested at Freightliner.

Sadly, very few Freightliner dealers we have found have actual technicians. They have went primarily with $125 per hour parts changers. As for air brake issue, same thing. We take it to someone to actually diagnose the problem. If you don't, you wind up with a compressor, lines, and dryer because they usually can't figure it out.

 

[Slo-Ride]

My lil Gremlin right now is the brake warning light and low air buzzer coming on and off. It also drops out the cruise control and on occasion makes what I think is the r/front head light flash bright and back to dim. Brake light goes out when I set parking brake and come on when I release brakes.Nothing wrong with the air system that I can see (other then this problem) I assume its the low air pressure switch not resetting and am told its back by the rear axle in that set of valve blocks mounted on the frame X member.
Before I attempt to change it out was wondering if this is something I should attempt in my driveway or let a dealer do it..
I cant really see how all that comes apart yet without tearing into it. @ this point I feel it may be best to let freightliner do this unless someone tells me its fairly simple process once ya get started. Parts man showed me the valve and it appears they are sealed against one another on the the sides with O ring gaskets??? Just under a $100 for part only. Any help or suggestions would be appreciated

I did have the blinker problem when truck was new and freightliner changed the whole assembly and no problems since..

 

[davekc]

Assuming the cruise is not on the turn signal assembly, the bulk head module again is where I would look. If it is in the turn signal assembly, then replace the multi-function switch. About 49.00 dollars. Some trucks have the cruise and headlight voltage going through the same module.
The brakes could be one of the modules or wires going to them. There will be three of them on the frame rail. The other do it your self gig is to inspect very carefully the brake chambers on the rear axles. Lost dust cover (dirt in the chamber) or a hair line crack will give you those symptoms. Sometimes it will back flow to the control knob on the dash and you think it is leaking there. Not usually the case. 9 out of ten times it will be a failure at one of the chambers.

 

[Slo-Ride]

Dave was your last post responding to mine or Truckblues post?
If to mine,,I have no air leaks or any proplems what so ever with air system other then the dash brake light and low air buzzer going off..
Sorry if I am mis understanding ya here..

 

[davekc]

When the buzzer goes off, is it holding the correct pressure?

 

[layoutshooter]

M2's have problems with AMU's and some with brake system check valves I think they are called.

 

[Slo-Ride]

When the buzzer goes off, is it holding the correct pressure?

Yes all system are normal,,air builds good and air dryer pops off at correct pressure..
Just the Red brake light in dash panel and low air buzzer wont reset themselves.. I can sometimes run 150 miles before the light and buzzer go out..Pulling the parking brake, the brake light will go off,,By releasing parking brake the light will come on.Buzzer (low air alarm)will not sound off until I actually get the wheels rolling..

(Sorry so late responding the dinner bus rolled thru the yard here and I had to jump in..or drive my own truck)

 

[Slo-Ride]

M2's have problems with AMU's and some with brake system check valves I think they are called.

These are the one back by the rear axle correct??
I tried getting some help at the woody-haven shop but ya can only guess where that took me. And to think they use to be versed in Expedite trucks

 

[Slo-Ride]

Now as far as the headlight problem, I have yet to cure that problem, and it has done it since the truck was new. The headlight is not actually going completely off,as we have had the headlight burn completely out and there is a noticeable difference. Got to be a ground problem, but where??

Mine when new had somewhat same problem of burning dim,looked almost yellow instead of bright white,(bad ground appearance).
I spent 2 whole shifts in Stoops freightliner shop in Ohio while they chased down proplem..from the shop time I had I know the r/front headlight circuit comes from the rear of truck,,they had my entire wiring harness out of the frame rails trying to find a voltage drop between the headlight and what Layout called the AMU. Cant tell ya exactly what they fixed but it was back by the rear axle as this was warranty work I got no paperwork on this one,,They also came up with a bad ground (plug) on one of the amber marker lights on the r/front fender..

 

[davekc]

Yes all system are normal,,air builds good and air dryer pops off at correct pressure..
Just the Red brake light in dash panel and low air buzzer wont reset themselves.. I can sometimes run 150 miles before the light and buzzer go out..Pulling the parking brake, the brake light will go off,,By releasing parking brake the light will come on.Buzzer (low air alarm)will not sound off until I actually get the wheels rolling..

(Sorry so late responding the dinner bus rolled thru the yard here and I had to jump in..or drive my own truck)

Low pressure switch/sensor is the culprit. If by chance that checks ok, then the check valve or brake module is bad or the wiring to those units.

 

[layoutshooter]

These are the one back by the rear axle correct??
I tried getting some help at the woody-haven shop but ya can only guess where that took me. And to think they use to be versed in Expedite trucks

Yes, the one back by the rear axle. I have had it fixed a multiple shops. I get it fixed, then a couple of more times till that warrenty runs out, buy another and start over.

EVERY shop I get it worked on in tells me the same thing. They are plastic, can't hold up to the vibration/pressure and break. They tell me that FL is aware and has done nothing to fix it.

 

[RETIDEPXE]

"EVERY shop I get it worked on in tells me the same thing. They are plastic, can't hold up to the vibration/pressure and break."

Maybe a fluke thing for me, and please understand I am no factory trained tech, but after having the AMU that controls the air pump cycle time, installed under warranty at 73k mi.s, the air pump starting cycling again every 5 minutes or so at 150k mi.s.
To save a trip to the dealer, I spent $75 for the new and installed myself. I completely dissmantled the old AMU and did not see any cracks or issues with it whatsoever (however I did not have the knowledge to test the little electronic pressure solenoid thingy but it looked OK). What I did find is the 'c' clip used to attach each AMU to each other to be flimsy and easy to slide in incorrectly if not careful. Also, the clip needed a few light taps with a small hammer to seat it completely thereby sandwiching the rubber gasket tightly between each AMU, a step I theorize was not taken at the shop or at assembly. I have not had a problem with this particular AMU now for 330k mi.s! I also gave all the other 'c' clips a few taps while i was at it.
I'm not sure about the red brake light/warning buzzer issue part needed, but when my brake tail lites quit, I replaced the stop light switch AMU in the FL dealers parking lot in about 20 minutes time. FL dealer wanted an hour and a half and could not get to it untill the next day. Be sure to have a certified brake tech sign-off on your brake repairs. Here's a link that my help on the signal/brake lites, may have to click on the "download" document link;

https://secure.freightliner.com/acc...ublic/m2bodybuilder/component/ma5428000wm.pdf

I don't mind the $125/hr rate if someone knows what they're doing and only charges me for real time spent, but to pay that for someone elses education using my truck and my wallet as the test lab irks me to no end!

Retidepxe

 

[RETIDEPXE]

I also found certain wire connectors on the M2 to be quite small and succeptible to intermitent contact at times. Regarding the turn signals/wipers and the headlights off and on, I took an eye glass repair kit regular head screw driver, because it is about the same width as the female wire connectors, pressed it inbetween the back side of each female connector and the plastic housing and bend the tool over slightly so that the tip of the tool collapses the female connector about half way down leaving the opening intact for each pin insert. This tightens up the contact with each pin.
Do this to both plugs going to the turn signal stock (smaller plug less noticible behind the switch) and both plugs at each headlite bucket. This solved these issues on my M2 so far. I did have to replace one of the headlite bulb sockets due to installing a higher wattage bulb that melted the socket. My right side low beam will still blink for an almost inperceivable split second maybe twice in a week, but does not bother me.
The more I learn about big trucks, the more I realize it really is easy to do self repairs/adjustments if one wants to save some real money. Lots of info online. I also do my own overheads on an Cat Acert C9, takes about 45 minutes, dealer charges $350! Why so much??? i mean, if an ameture can do it in 45 minutes, and I mean double and triple checking lash after adjusted, why does it cost so much on an electronic engine? I can understand it somewhat if a mechanical motor and injectors need adjusting also, but on an electronic motor, to turn crank to TDC, loosen 6 lash adjusters, adjust, tighten, check and triple check, turn crank 360 degrees and repeat, I don't get it......I can't stand it and I'm not going to take it anymore! Who's with me??

Retidepxe