August 21

2014 Mercedes ML550 Electrical Issues



Mark: Hi, it's Mark Bossert. I'm here with Mr. Bernie Pawlik, Pawlik Automotive in Vancouver. Vancouver's best auto service experience. 25 time winners best auto repair in Vancouver as voted by their customers. And we're talking cars. How are you doing, Bernie? 

Bernie: Doing very well today. 

Mark: So today's victim is a 2014 Mercedes ML 550. What was going on with this vehicle? 

Bernie: So this vehicle was barely running when it came to our shop and it had been at a Mercedes dealer, to have it repaired which they brought to us instead. There was apparently a water leak in the passenger side floor, some wiring damage was what we were told when the car came in. The dash was lit up with numerous warning lights. It was barely drivable. Transmission wouldn't shift properly. So that's how it came in. 

Mark: This is pretty catastrophic, multiple issues. And how do you proceed with testing and diagnosis when it's that kind of issue?

Bernie: Yeah, well, obviously the first thing we'll do is plug a computer in, scan it. And we did that and found a slew of codes a mile long. You know, had the customer just brought it straight to us. I mean, we would have had to dig in a little further, but knowing that there had been a water leak and that it had been looked at we proceeded to remove everything. Mercedes put everything back together.

So we took the passenger seat out, which is where the battery is located and all the main fuse panels. We started examining the wiring and what we found was just, it was horrendous. We didn't find any water in the floor. It was all gone, whether Mercedes removed it or some evaporated. We don't know. But there was no water there, but the damage was pretty severe.

We'll look at some pictures shortly because I've got lots of them, but basically the battery sits under the passenger seat and there's a number of main fuse boxes. There's wiring connectors. There's of course, modules of all sorts underneath there. And there's a deep well, so water can sit down inside this area. And I mean, there's no drains there probably because it's low in the car. You don't really want holes in the floor either. So anyways that's basically what we found. And you know, developed a repair plan from there.

Mark: So what was the repair plan? How did you proceed? 

Bernie: Well, what we ended up deciding to do was to find a used vehicle from an auto wrecker and buy all the fuse boxes and wiring connectors and modules that we needed to replace it. I mean, from a car that hadn't been flooded, no problem.

I mean, everything's going to be in good condition cause it's out of the way. And, you know, there's no environmental problems. So we're able to find an ML550. Acquired everything but the transfer case control module. This vehicle is I guess not every model has this, but this had a two speed transfer cases.

I guess it's like the deluxe fully optioned model, it kind of remind me of a Range Rover. It had controls for all, you know, little dials. You could turn and sport mode, off road, you know, sandy mode. It's kind of like a Range Rover clone. The air suspension can go low and high and had a two speed transfer case as well.

So it had a lower gear range, which seemed to be a hard option to find. So we bought a new module for that, which wasn't a crazy amount of money. So that's the only part we replaced with brand new. Otherwise, we got everything used. 

To get it new, the only way you'd be able to buy it from Mercedes. I'm sure these fuse boxes are available, but all the wiring connectors going into the fuse boxes, and there are many of them, were all severely corroded. Plus, there was a main wiring harness that ran underneath the floor. And this is like a, again we'll see pictures. The connectors were basically corroded. Some of them actually had disintegrated. And again, those would require replacing a whole wiring harness.

And I don't even know where, you know, I can only say that it starts in the floor, but where it runs to, that could involve, like, days and days of work, taking the dash and the back of the car apart to change the wiring harnesses. So it would have been exceptionally expensive, not only in parts, but in money.

So we're able to for a fairly decent price, acquire these used parts. We just clip the ends off the wiring harnesses and then soldered and heat shrink all the wires. So very, very labour intensive job. But, you know, much less labor intensive than it would have been to change the whole wiring harness.

Mark: Let's go to the map. Let's see what it looks like. 

Bernie: Yeah, let's go to the pictures because yeah, some pretty neat stuff. So there's the car completed and looking good. 2014, so it's 9 years old at this point. I think only had 88,000 kilometres. So still pretty young, not not much mileage on the vehicle. 

2014 Mercedes ML550 Electrical Issues

There's a view. You can see the red arrow. This is a connector. I'm going to be moving my mouse pointer around for a lot of these pictures. There's one connector that we replaced, there's another one right beside it. You can see a lot of sort of just green stuff around here. This is a wire that went into this black connector here that is basically broken off. You can see it just corroded and disintegrated and broken off. So pretty large gauge wire, a main power connector of sorts. 

2014 Mercedes ML550 Electrical Issues

Next picture, this is a view, we did replace the battery because it was dead. Needed to be replaced. So this is our new battery. This is the probably I guess the main power fuse box. You can see a large power cable here. I'm trying to discern whether this was the new or used part. I think this is still the old stuff in the vehicle. It looks kind of grungy and corroded.

2014 Mercedes ML550 Electrical Issues

There we can start to see some ugliness. So this is right near that wiring connector. I showed in the first, you can actually still see it, you can see that broken off wire right there. Yep. You can see this the sensor here, I think this is a yaw sensor or something for the vehicle dynamics control.

2014 Mercedes ML550 Electrical Issues

This had been submerged in water. This connector had all like green in the pins. So this piece we replaced along with this sensor here. You can see corrosion on this. This fuse box completely destroyed, all the wiring underneath it, all replaced. 

So again, here's the wiring. You know, we basically pull this out, cut the wires off somewhere around this area and then replace them all. A lot of these larger cables I was able to replace again with used ones. Although this large one here, I think, ran to the front of the vehicle under the hood. We're able to salvage the old one. It wasn't too badly damaged.

So kind of gives you an idea of some of the things and we'll just keep looking at more corroded wire pictures. Again this is the main fuse box. If you look at the bottom, you can see sort of just general ugly, ugliness. 

2014 Mercedes ML550 Electrical Issues

Mark: It was a swimming pool. 

Bernie: It was a swimming pool. Yeah, absolutely. This is the replacement harness. So when I went to the wrecker, I clipped it off maybe six inches away from where the edge of the picture is here. And unfortunately this isn't the sharpest photo, but it's actually, no, this actually, this is the old one too. I can see corrosion there. You can see green corrosion. So I thought I was showing something new, but the new ones are not as exciting.

2014 Mercedes ML550 Electrical Issues

Another view of corroded wires. And I thought I'd talk to you about how we do wiring repairs in our vehicles.

2014 Mercedes ML550 Electrical Issues

So you know, it's really important to repair these wires like original, like you do not want to have a bad connection here because down the road, whether it be 6 months, a year, 10 years, however long the car lasts, you know, I don't want someone to have a problem with this particular issue.

2014 Mercedes ML550 Electrical Issues

So how we chose to repair is, first we use a bare butt splice connector. So what this does is, we have a crimping tool. We strip the wires, we crimp it. So that's the first stage of the repair. Now, that actually is a good enough connection. We tug on it. It doesn't come apart, but, you know, it's still not as good as I'd like it to be.

So the next repair is to solder it. Sorry. This picture is incredibly blurry, but you can see a little bit of solder there. So I solder this connector to the wires. 

2014 Mercedes ML550 Electrical Issues

And then as a final step, cover it in heat shrink tubing, and this heat shrink tubing actually has some kind of sealant on it too. So it seals the wire from moisture. So this is like the ultimate repair, you know, nothing's going to come apart. Nothing's going to break or corrode. 

2014 Mercedes ML550 Electrical Issues

So that's the kind of quality of repair we do in these things. It takes more time, but, you know, I don't want to have to deal with like, oh, maybe there's a problem with that or someone down the road.

A couple other views. This is that connector. I showed near the beginning. You can see where the broken wire, the black connector. A lot of corrosion here. It's hard to kind of see this, but these pins are all green, corroded and they weren't fitting properly. And actually one of them had actually completely disintegrated. It wasn't even there. 

2014 Mercedes ML550 Electrical Issues

Again, another view. Remember that wire first showed at the beginning with the arrow, that's where that wire used to sit. And so again, it gives you an idea of the corrosion. 

2014 Mercedes ML550 Electrical Issues

And this is the new stuff. So these are the new wiring ends. You can see that, you know, they're shiny, clean, the pins sit properly.

2014 Mercedes ML550 Electrical Issues

And I believe we're getting to our last picture here. There's again, another view of the corrosion in the back of that multi pin harness. You can see how many wires there are here. I think there was like, 30 or more wires here, various gauges that had to be replaced. So it was a very, very long job, but you know, do it properly. Do it right. 

2014 Mercedes ML550 Electrical Issues

Mark: So I guess my first question is why would Mercedes put the battery in such a place that could fail so catastrophically. 

Bernie: Most cars do stuff like that. You know, there's so much on a modern car and every manufacturer, you know, they put battery wherever they can, because there's no room under the hood for a battery, like there used to be.

Sometimes they put them in the trunk. There's actually a little mini tiny maintenance reminder, or it's like a little mini battery that powers some of the electrical stuff in the trunk, it's minuscule. But, you know, any vehicle manufacturer, they put the wiring, they put it wherever they can.

And this is why, of course, when you look at this, you know, this is why you don't want to buy a vehicle if it was ever in a flood. Because this is the kind of stuff, you know, when water runs over into a vehicle and isn't removed. I mean, if you could get it out immediately you could probably save some stuff. 

The other thing I don't have a picture of, is there's a module on the side of the battery. This is for the transfer case control module. I thought, can we reuse this? Fortunately, we're able to open up the module. Look at the inside full of like, green corrosion. Junk. So there's so much like, you know, a vehicle that gets in a flood. That's why they get written off is because there's just so much that can be damaged. So expensive to repair. 

Mark: So, you also mentioned that the vehicle was originally diagnosed at a Mercedes dealer and then ended up being coming to your shop. Why? Why did the owner choose you guys? 

Bernie: Well, I think probably because we were willing to repair it. I think, I don't know for sure. Because I never talked to them. But I would assume the way the way Mercedes likes to deal with stuff is if there's like a corroded wire somewhere. The only way they're ever going to repair it is to replace everything. The whole thing. 

And I've heard stories. I know another shop owner, I think it was an SL 500. It had some corroded wire in the back and they wanted to replace the whole wiring harness for S30,000. It was a $30,000 thing, which I'd say that this job, if Mercedes was going to do it, it's probably a $30,000 job. Who wants to spend that kind of money. 

And then, you know, as I say, the example of this other Mercedes, this guy had fixed, it was like a wire and just need to be connected and crimped and soldered, heat shrink. I think he said, like, $150, $200 or something was the repair bill. So, I mean, they're not interested in doing creative repairs. They're only interested in, they want to sell you a car. They'll service it. And repair it the Mercedes German way. I'm German, not an insult.

There's a German precision way, but there's, you know, to me, that comes at a sort of level of arrogance or lack of willingness to do things. I actually did most of the repair work on this. Found a kind of a gratifying repair, you know, being able to take something and fix it.

Mark: Well, I guess the question is, with that much work, it obviously was an expensive repair. Was this repair worth the money or would it have been better to, it's like you said a 9 year old vehicle, would have been or just to say, well, goodbye. Get a new one. 

Bernie: I think so, because, I mean, they only had 88,000 kilometres and I don't keep up on used cars, but I would imagine this thing must be worth at least 30 to 40,000 dollars and good running condition and cleaned up and neat, detailed. You know, next to the AMG model, this is like the top of the line vehicle. So, you know, twin turbo V8. It goes pretty good for an SUV. But you know, yeah, I think it's worth it. 

I mean, if the owner had said, hey, I don't want this anymore, I would have gladly scooped it up for a very low amount of money and fixed it and sold it myself. You know, those kind of vehicles would be worthwhile. But apparently Mercedes wouldn't even take it for a trade in. So, it's just interesting how they operate.

Mark: So how did the ML550 work after all that hard work to get it repaired?

Bernie: It was good. And I do want to mention that the transfer case module didn't need to be reprogrammed too.

So there's some programming and things that need to be done to get everything working. But yeah, ran great. I cleaned up everything, cleared codes. And then had the module reprogrammed and it works like new. Runs great. I took it for a couple of very long road tests because of course, a very extensive amount of repairs and one to test everything out and everything seemed to be working fine. So it's good. Happy ending. Just like we like.

Mark: No more Christmas tree dashboard. 

Bernie: No, no, everything's off. It's good. Yeah. 

Mark: If you're looking for service for your Mercedes and they don't want to deal with it at the dealer, come and see Pawlik Automotive in Vancouver, BC, Canada. They'll look after you. They'll make it better. They will fix your car, get it running great. You can book online at Or you can call them at (604) 327-7112. You have to book ahead. They're always busy. Pawlik Automotive, Vancouver. Thanks so much for watching and listening. We appreciate it. And thanks, Bernie.

Bernie: Thank you, Mark. Thanks for watching.

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Bernie Pawlik

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