AGuess
Elite Veteran
Date registered: Apr 2006
Location: Holly Springs NC
Vehicle(s): 93 500GE, 93 500GE, 2002 G500
Posts: 717
| 2014 G550 Locker Help Needed
Hi Everyone.
Background. My lockers worked before my rear axle was replaced by MB, due to vandalism (tick tock lug bolt challenge). Although it has been about 6 months since I last used them.
While MB had the G, I asked them to make sure everything worked. They said the front and rear locker would not engage and that it was not caused by the accident. so not covered by my insurance. They said they thought that my two differential lock control cylinder's were bad. Part number: A000 353 29 55 and they wanted 12 hours of labor plus parts to replace. I did not have them do the work.
I ordered the two cylinder's from MB Classic and was going to replace them today. However, I found before replacing them that my locker switch (three switches) does not light up or engage the TC, front or rear locker. These are just vacuum controlled diaphragm units.
The MB mechanic, told me that the TC switch was lighting up when he was trying to figure out the problem, but the front and rear locker switch would not light up. Now nothing lights up.
I confirmed that the fuse (located in rear cargo area (7.5A) is good and that I have power to the switch control unit. I also pulled the control unit and tested power at it.
I confirmed that the Vacuum pump and the vacuum actuators are working.
I read that to bleed the lockers, you open the front valve, let the fluid run, open the rear valve, let the fluid run until no air, then close the front valve and then the rear. I did that using a brake bleeding pressure unit. The switch does not engage the lockers.
I also hooked up my star diag computer and used it to test things, which did put the TC in low and high, so that is working. My SAM unit's are all ok.
Thoughts?
1). Should I order a new locker switch.
2). Should I replace the two lock control cylinder's? I held off, so I can return the parts if not needed.
3). Are you aware of any other fuse that might control something?
4).Other things to test or look for.
MB is not going to fix this under their original work, so I appreciate your knowledge and advice.
Thank you in advance.
AGuess
|
oskar
Elite Veteran
Date registered: Sep 2006
Location: Lyons, CO
Vehicle(s): 1981 280GE, 2002 G500, 280SE 4.5, Audi A4 1.8T
Posts: 708
| Re: 2014 G550 Locker Help Needed
Normally, the front and rear locks will not engage unless the center (TC) lock is
Does the vacuum pump come on once you try to TC lock - switch #1 ? |
Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3185
| Re: 2014 G550 Locker Help Needed
When you switch on the TC locker do you hear the pump? Does it continue to run or does it eventually stop? As Oscar says, if the TC does not engage the front and rear will not engage until it does. Sounds more like a vacuum loss to the TC.
Depending on your model year with most 463s there is a solenoid/changeover valve for the TC mounted to the firewall on the left side of the air intake. There are vacuum lines attached here. Is any of these are disconnected the TC locker will not work. The valves (valves) for the front and rear lockers are on the other side in the triangular box (if you have that) or next to the battery if it is in the engine bay. There is also a diaphragm at the front of the transfer case that actuates the lock. These diaphragms can tear or rupture making it impossible to activate the lockers. So before you start throwing money at replacing parts do some more diagnostics. |
