Our MB GL320 won't start. The first issue was the command system wasn't working. We replaced a fuse now the vehicle won't start. Although the command system is all OK now. Battery is OK.

 

Can you hear it try to start and the engine isn't firing, or nothing at all?

 

The engine wasn't firing at all, no crank. The first problem was weeks ago, the transmission wouldn't change gear. Error message "vehicle not in position P", that after a little trouble shooting changed to "drive to workshop without changing gear". A little difficult when it was stuck in Park. It was taken away on a tilt tray to the nearest dealer. (The tilt tray driver had to remove a wheel and place a dolly wheel on it to get the car rolling.) The transmission controller module was what the MB diagnostic software blamed it on.

10 days and $2300 later the car drove out of the workshop fine.

2 weeks later 500km from home the problem was back. The next tilt tray didn't have a dolly wheel and just skidded the tyres as he winched the vehicle onto the tilt tray. A day later in the holding yard of the towing company the car started fine and drove home without any issue.

By this stage we had noted the problem was associated with wet weather. For the next week we looked at the vehicle ourselves for many hours sometimes with a nephew who happens to be a qualified autoelectrician. We had a hose and a spray bottle and got some water about everywhere that rain might get in and got the problem to replicate a few times until we isolated the top left side of the engine bay as the problem area. Often we got the problem to occur and then left the vehicle to dry out before coming back to try and narrow it down some more on every occasion the problem went away when the vehicle had dried out. Without really doing anything the problem seemed to fix itself and now we cannot get the issue to reoccur.

However something we did had caused the command system to stop. We ended up driving the vehicle around for a day or two with no radio, Nav, telephone functions and a few other things like the CD/DVD players.

By Sunday when I submitted the new thread we had been working on the vehicle again for a few hours and managed to find a faulty fuse. Once it was repaired the command system was back on but the car simply wouldn't crank. Command would come on lights and accessories but it wouldn't engage the starter motor. If I tried to start the car in drive I got the error message about starting the car in N or P.

Only minutes beforehand we had started the vehicle and it turned over and hummed like a dream albeit without command. By this stage we had removed the battery terminal and cleaned the battery several times in the previous week and we were confident it was not a battery issue. That was when I sent out this thread, it was desperate times. We slept on it and came back to it this morning and found that a fuse located near the repaired fuse had been dislodged.

Reinstalled and the problem is fixed. The car is working like a dream since then although there is no rain in sight. It may be a dry weather vehicle from now on, we'll have to wait and see. Now I only have to talk the the local dealer about the $2364 fee they expect for supply and installation of a part that wasn't faulty and didn't fix the problem. I doubt there'll be a satisfactory resolution but at least my car is working again.

Hope this info helps others having issues with their merc.