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Hey folks. I've had this account for a while but have not posted that I remember. I'll try to make this as short and to the point as possible.
I bought a 2008 C300 about a week ago for $1,000. The guy said it sat for four weeks then it wouldn't crank. I had it towed home, charged the battery and it would not crank. Insert the key and you hear the zip from the steering unlock. Radio, fan, windows etc all worked fine, but not even a click when turned into start position. Also noticed that it did not display what gear I was in on the display and would not pull out of park unless I did it manually. I found a reputable MB mechanic and decided to have it towed there. As soon as the tow truck got to my house I walked outside and the running lights were on for some odd reason. I got in the car to assist loading it onto the tow truck and to my surprise, when I turned the key on it displayed which gear I was in. I turned the key to start position and it started! Now it will start about 50% of the time. When it does start I'm getting all kinds errors about lights out, then other times it doesn't give me errors. Sometimes when I pull the shifter into a gear, it doesn't engage, but most of the time it does. I can't figure this car out. This may be my imagination, but it seems like when I tap on all of the relays and fuses in the fuse box under the hood, that's when it will cooperate and start.
I know it may be a long shot, but if anyone has any insight, I would greatly appreciate it.
Take a look at the front SAM. I had many of the same issues and the front SAM was the culprit due to water intrusion.
You nailed it! There is a broken piece of plastic near the windshield wiper and it's dripping rain right onto the fuse box! Do you think I can get away with removing it and dying it out? Or is it toast?
Was the fuse box cover missing? I have seen some cars with a hole in the rubber around the driver windshield wiper shaft that leaks onto the sam area. I think a cover would protect it but I am not sure if the lid seals 100% or if people have had water intrusion even with the lid on
Was the fuse box cover missing? I have seen some cars with a hole in the rubber around the driver windshield wiper shaft that leaks onto the sam area. I think a cover would protect it but I am not sure if the lid seals 100% or if people have had water intrusion even with the lid on
Unfortunately, the lid was off for a couple of months when the previous owner had it. Rain water had been dripping directly into it.
Does anyone know how big of a process it is to remove the Sam? It looks straight forward if you just glance at it, but if someone has a bit more knowledge, I would appreciate it.
The sam is held in by 4 torx screws. The front two are easy, the rear too are a tighter squeeze. I used a 2-3 inch torx bit with a 1/4 inch wrench to turn the bit in the rear. When you go to remove the sam module its a tight fit with the windshield wiper linkage, I have removed it without moving the wipers but Its a bit easier if the wipers are half way through the cycle and in the middle of windshield so the linkage is less in the way above the sam. There are a few relays that can be removed to make it a bit easier to clear the linkage so take a pic of the sam before you remove relays for reference later. I worked the front of the sam out first and once its tilted up enough it should slide out. Its a tight fit in the lower plastic housing but its really not too bad. There are like 20+ connectors on the bottom side that are color coded and only go in one place except the big power cables at the front and rear. Take pics along the way just in case and the bigger power cables on the end are a bit tricky. I can try and take a picture of the ends so you know how they unclip. Those took me a while to figure out but once I did they were easy
The sam is held in by 4 torx screws. The front two are easy, the rear too are a tighter squeeze. I used a 2-3 inch torx bit with a 1/4 inch wrench to turn the bit in the rear. When you go to remove the sam module its a tight fit with the windshield wiper linkage, I have removed it without moving the wipers but Its a bit easier if the wipers are half way through the cycle and in the middle of windshield so the linkage is less in the way above the sam. There are a few relays that can be removed to make it a bit easier to clear the linkage so take a pic of the sam before you remove relays for reference later. I worked the front of the sam out first and once its tilted up enough it should slide out. Its a tight fit in the lower plastic housing but its really not too bad. There are like 20+ connectors on the bottom side that are color coded and only go in one place except the big power cables at the front and rear. Take pics along the way just in case and the bigger power cables on the end are a bit tricky. I can try and take a picture of the ends so you know how they unclip. Those took me a while to figure out but once I did they were easy
That is another issue. When I bought the car, someone had already messed with the fuses and relays. Plus there were a bunch sitting in the cup holder. I put them back in the best I could and got the car running (occasionally with a few taps on the fuse box/sam), I replaced a few with the ones that were in the cup holder and now it won't start at all. Basically, I need to know what relays go where so I can reinstall everything after I dry out the sam. Any idea where I can find this information?
hey i had the same exact issue w my car when i got it...no fuse box cover...all kinds of electrical issues such as trouble starting, windshield wipers not turning off, lights staying on after car was turned off...dealership told me it was the front sam and they wouldn’t fix it even though i had a warranty. what i did was order a new (used) one off of ebay and literally did a swap out from the old to the new. as soon as i did that, the car started up w no issues. also, i switched my battery out since it was the original one and that’s helped a ton too.
‘also...invest in a fuse box cover so it won’t happen again. i think i got mine for $30 or so.
Last edited by ruffin2000; 02-16-2021 at 06:48 AM.
Reason: forgot one other thing
The sam is held in by 4 torx screws. The front two are easy, the rear too are a tighter squeeze. I used a 2-3 inch torx bit with a 1/4 inch wrench to turn the bit in the rear. When you go to remove the sam module its a tight fit with the windshield wiper linkage, I have removed it without moving the wipers but Its a bit easier if the wipers are half way through the cycle and in the middle of windshield so the linkage is less in the way above the sam. There are a few relays that can be removed to make it a bit easier to clear the linkage so take a pic of the sam before you remove relays for reference later. I worked the front of the sam out first and once its tilted up enough it should slide out. Its a tight fit in the lower plastic housing but its really not too bad. There are like 20+ connectors on the bottom side that are color coded and only go in one place except the big power cables at the front and rear. Take pics along the way just in case and the bigger power cables on the end are a bit tricky. I can try and take a picture of the ends so you know how they unclip. Those took me a while to figure out but once I did they were easy
I can not figure out how to get those two red wires disconnected! Any tips or tricks? I have everything else disconnected.
Push the plug back in the sam module so there is no tension on it as you try and release the clip. I use a flathead to put some pressure on the release tab and pull. It doesnt take much pressure or effort at all if you are pushing in the correct spot
02-13-2021 | 11:36 AM
