No Wipers/Hazard/Alarm after new battery
 

I am new to this group and I apologize if I ask something that has been answered before.
My 2001 C320, out of warranty now, needed a new battery and I thought I would save some $ and replace it myself (stupid me).
However, after replacing it, the following items are no longer operational:
1. Wipers
2. Hazards/ Turn Signals
3. Rear sunshade
4. Trunk won't open from inside switch
5. Key remotes won't unlock trunk
6. Key remotes won't unlock doors, unless key is 1 foot or less from door
handle (I checked the batteries and both remotes)
7. Alarm
8. Fuel gauge shows 0 fuel all the time
9. The message display on the dash says 'Faulty Display'.

The wipers were acting funny a day before, when I had them on intermittent.
I was also getting strange error codes on the day the battery was low.

I checked all the fuses and none are blown.

I scanned the boards and found that this is more likely because a few relays have failed. Please let me know if you think this is the case.

If it is, could someone offer some help on how to identify the defective relay?
I see those 'cubes' on the fuse boards, are those the relays? How can I find out which ones correspond to the functions I described above? Lastly, where can I buy relays? (fastlane has none for my car)

I may sound like a novice when asking these questions, but this is not the case. I have performed major mechanical repairs on my cars, just not electrical. Yet, I have fixed electrical components for TVs and applicances. Bottom line, feel free to give advise that is complex to follow. Its not that I can't do it, but I won't touch this car's electronics without getting some advise first.


Thank you in advance!

I hate to ask this but I have known it to happen, could you have hooked the battery up backwards? Sounds a lot like reverse polarity. Just a thought. :o

I thought it was obvious that I did, otherwise my complaint list would include 'car won't start', 'smell of blown electonics', etc.

In other words, the car is perfectly drive-able, all other electric/electronics work, including headlights, radio, A/C, ESP, locks, etc.

The problem must be isolated to one or more relays, I think, I just need someone to confirm.

Thanks

Further checks
 

It may be prudent to attempt some furthur diagnostics. As in, replace the fuse that powers the fuse with a known good fuse.

Failing that, what power is going to the display proper? Should be a fused line terminating at the connectors feeding power to the display. If you have 12volts there, could just be a coincidence that the displayed failed at the same time as the battery (low voltage will cause a higher current in electronic equipment).

Ron

did you ever find the problem?
 

did you ever figure out what was wrong? my car has the same issue and I really would like to repair without visiting my dealer.

sounds like you need a new rear sam, don't know why it just happens sometimes(so I have heard)

Sam?
 

What is a SAM? New cars have way too many fancy and expensive electrical parts.

basically a fuse box

been their and passed it to dealer
 

I just passed on a car with the exact situation yesterday. I also assumed it was the rear sam; however, I was not ready to start shotgunning on my customers dime. It has been driving me nuts on the actual cause of the failures.

SAM or Signal Acquisition Module is basically a controlling fused relay unit, their is one in the boot (rear SAM) and one in eng bay (front SAM).
They control things via CAN signals, like boot release, turn signals, fuel level, brake lights and so on.
When the battery is replaced or jump started without precaution, a voltage spike occurs, this high spike is the biggest killer of sensitive electronic components.
As far as the rear SAM failing I have opened several to see if there is any visible damage but found nothing, from what I can gather this voltage spike wipes the memory chips or roms within the circuitry, no matter what you try, you just can't reinstate communication and it has to be replaced.