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Ask Michael Warfield Your Own Question
Michael Warfield
Michael Warfield, Factory Mercedes-Benz Technician
Category: Mercedes
Satisfied Customers: 3130
Experience:  Mercedes-Benz Master Certified technician
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I have a 2003 mercedes benz c240 ... months straight my

Customer Question

I have a 2003 mercedes benz c240 ...for 6 months straight my electricity would randomly tweak ...and the cluster would read 185f,the headlights will flash on and off even when the lights arent even turned on ,the high beam signal flashes on and off on my dash, the horn, turn signal, radio, windows, heat, wipers , and interior lights alll dont work at the same time ...then it would randomly go back to normal for a week straight at some points and then go right back to tweaking pleaaaseee do u know the answer to my problem no mechanic knows..ive tried replacing the sam module already that didnt work . And sometimes when its tweaking i could hear a little clicking sound going off in the back it sounds like.
Submitted: 1 year ago.
Category: Mercedes
Customer: replied 1 year ago.
Also the gas hand always goes to empty even if the tank is full and the gas light is on when the electricity tweaks
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 1 year ago.
Dont call just type answer sorry and its taking pretty long whats the problem?
Expert:  Michael Warfield replied 1 year ago.

Sorry it took so long, I don't get home from the shop until the afternoon/evening. There are actually 2 sam modules, the rear sam controls and sends the signal from the fuel level sensors to the instrument cluster. Was the front sam replaced? Was just the sam module or the entire sam with fuse and relay box replaced?

Customer: replied 1 year ago.
We switched out the front sam module there was no effect ...i dont know about the relay box though
Customer: replied 1 year ago.
have u seen this problem before?
Expert:  Michael Warfield replied 1 year ago.

The sam module actually plugs into the backside of the fuse and relay box. I usually recommend replacing them in pairs because the fuse box can get shorted internally.

Expert:  Michael Warfield replied 1 year ago.

Yes, I have seen it before. It is a CAN network issue, usually caused by the front sam/fuse and relay box. I've always just replaced them in pairs because I have seen one damage the other. It is a little weird that your fuel gauge is dropping...that signal is sent by the rear sam.

Customer: replied 1 year ago.
Ok so i know youre probably not 100% sure since ur not here physically ..so what u reccomend is i get a new sam module and what else ?
Expert:  Michael Warfield replied 1 year ago.

Well, first double check that the fuse and relay box was replaced with the front sam. If it wasn't, I would make sure you replace that first.

Customer: replied 1 year ago.
Ok so its 3 things fuse box,relay box , and sam module correct? ...and is all that under the hood ..
Customer: replied 1 year ago.
they switched the sam back out since it didnt work
Customer: replied 1 year ago.
Because i know its a fuse box inside the car and in trunk i just dont want to get those confused
Expert:  Michael Warfield replied 1 year ago.

Well 2 things. The fuse and relay box is just that, a box. The sam module slides into the backside of it. I suggest replacing both of those parts at the same time.

Expert:  Michael Warfield replied 1 year ago.

Used ones are a lot cheaper on ebay. Are you using new parts?

Customer: replied 1 year ago.
No i bought a used sam module off ebay ...what else u suggest i buy im sorry im just kind of getting confused not knowing if its 3 or 2 things...so now i have to buy the fuse and relay box is that one thing or two lol sorry
Expert:  Michael Warfield replied 1 year ago.

Did the sam module have any fuses and relays on it?

Expert:  Michael Warfield replied 1 year ago.

Or was it just the module?

Customer: replied 1 year ago.
No it was just the module wasnt any wires on it
Expert:  Michael Warfield replied 1 year ago.

This is the complete assembly you need.

Customer: replied 1 year ago.
Ok im going to do that ...you can still be here after i fix the car to let u know how things went right it wont be a sperate question right?
Expert:  Michael Warfield replied 1 year ago.

It won't be a separate question. Let me know how things go.

Expert:  Michael Warfield replied 1 year ago.

I may not be able to get back to you until the afternoon, evening though.

Customer: replied 1 year ago.
Oh thats fine that website was just misleading saying they can usually respond in 10 minutes and i asked the question at 7am
Expert:  Michael Warfield replied 1 year ago.

Yes, if its an easy question for the average expert. Your problem needs a mercedes specialist with more intimate knowledge of your car's systems.

Customer: replied 1 year ago.
Aw ok thanks alot ill be back in touch soon
Expert:  Michael Warfield replied 1 year ago.

Ok, good luck!

Customer: replied 1 year ago.
This is what i replaced ....i think i confused you because this looks like what u sent me
Customer: replied 1 year ago.
it looks like the sam module and fuse and relays together
Expert:  Michael Warfield replied 1 year ago.

Yes, that is the front sam for sure. Did you have the same exact symptoms with the front sam replaced? You said that someone put one in and then removed it when it didn't fix it, correct?

Customer: replied 1 year ago.
Yea it did the same exact thing i didnt even realized he switched it out cuz nothing changed when he did it
Expert:  Michael Warfield replied 1 year ago.

Did the mechanic every give you a copy of the "quick test" or "short test" if he did one? If not, is it possible he could get you one? I would like to read all the can fault and event codes. I should to be able to determine a lot more just by that test.

Customer: replied 1 year ago.
No he didnt or cant do it not at the location im at i didnt go to an official benz shop because they cant work with my warranty...thats why i was questioning you
Customer: replied 1 year ago.
I asked what happens if i cant get a short list my mechanic is saying he doesnt have the software for that
Customer: replied 1 year ago.
the dealer was wayyyyy too much money to even diagnose thats why i was asking you