Need help with battery/starting issue please on a 1999 C280!!
 

Last Thursday, I took my car to a mechanic to double check what I thought was wrong with my a/c. Yup, compressor is gone, and they told me to replace the dryer (yes, I know) and the expansion value (yes, I know). Also pointed out I had a bad tire (woops, didn't know that). So I got home, parked the car like always. Next day, Friday, I went out to pull it close to the garage to throw the spare on so I could take it an have new tires put on and the car was dead. I mean D E A D. I was like ok, did I leave the lights on or something? So, I got the car jumped that night, drove it around for a while. Saturday morning got up and yup, car was dead. My b/f was telling me it had to be a draw. He said it had to be the radio because it never worked and then all of a sudden I managed to get power to it and it was requesting the code. I entered the code and all it would do is say "WAIT". That's it. At one point, the car wouldn't start unless you entered the code into the radio. So I ended up pulling the radio completely out of the car. At this point I'm thinking the battery is bad or the alternator went out. Got the car jumped again and took it to Advanced Auto. They told me nope, both were good, just battery was low and needed to be charged. So, ok I drove the car for a while, took it home and parked it. Monday (yesterday) went to get in it and don't you know yup it was dead. So it obviously wasn't the radio. This time I called AAA because I know if they come and give you a jump, they can test your battery and alternator too, While I was waiting for them, I decided to clean the terminals, again. I got them super clean this time. I decided what the heck. Lemme see if the car will start. Don't you know it did. It was a struggle to start, but it did. I ran it about 10 min. Shut it off and tried to start it. It lit right up. This morning, yup it's dead. Can someone please tell me what the heck is wrong with this car. I only know Chevy's. This is my b/f car and it's driving me crazy. I have never in all my years of working on cars seen a car do this. You get in, all the lights are on. Put the key in the ignition, all the lights in the dash come on, beeps and all. Turn the key and........nothing. I mean NOTHING. Sometimes maybe a cough, but that's it. Anything you guys can suggest would be appreciated.

Thanks again

Maybe check the water level in the battery.
*edit - distilled water

Thanks for the suggestion. Although I haven't seen a battery where you can check the water level in a long time (most of them are sealed now), I looked this morning. The battery that's in the car is a sealed battery as well. There was no way for me to check the water level.

I thought to through my OBDII scanner on it this morning. No codes either......:nix:

Did more investigating today. Decided to put the radio back in. Untangled all the wiring before I did. Don't know what made me try to start the car after I hooked everything up but BEFORE I pushed the radio back in the dash....... don't you know the car started...... I have a short somewhere in the dash. I have no idea where to begin to start looking for it. I left everything where it was and I'll see if it still starts later.....:confused:

Having the battery charged back up by a shop doesnt mean the batteries going to "hold" a charge. It just means it's charged up. I have many older batteries charge up nicely only to have them die again within a few days.
If it doesnt hold a correct charge, it's time to replace it. Days of distilled water are long gone - better off picking up an replacement AGM battery that has the cranking power (and good warranty)

For these older MBs, I'd still go back to the basics and OWN a scanner (best investment for yourself), check the MAF, fuel filter, etc.
I'd also go thru the motions of using Berryman treatment for these older toys; do this all the time ours and colleagues rides, gas generators, etc. With older pre-owned MB car purchases where you really dont know
it's service maintenance history unless the previous owner's kept good records.
Just my 2 cents :)

I took the battery and had it tested at Advance. They told me it tested o.k. I have an OBDII scanner that will also read live scan. The car has not thrown a code. I'm almost positive that there is a loose ground in the dash. If you look at my last post I messed with the wiring for the radio I had pulled last week and the car started. I did nothing else to the car other than that. Prior to that, the car was dead. I turned it off and left it alone. Came back to it a couple of hours later to start it again which it did after several attempts. Had this been yesterday BEFORE I messed with the dash, the car would have been dead again. So now I have the joy of ripping the dash apart with no service manual and I can't locate one anywhere nor can I find where to download one for free or extremely inexpensive since I've been out of work for a year now. (Yes I need a car to drive however I can't spend $20+ on a book)

Is this an oem radio or aftermarket you pulled?
I'm dumbfounded as to how pulling a radio out and untangling the wiring (harness) behind the dash would affect the MBs ability to start or not start. Perhaps retrace back your steps and what you did as you were untangling wires to bring back the 'no start' issue?
You stated it only started "after several attempts..." This doesnt seem to be a grounding issue from your wiring harness untangling process. There's got to be more than this simple presumed conclusion.

Getting back to your battery comment, it "tested ok", again, I've heard same comments back from MB- Indies only to find out down the block, the battery is 'not ok' and doesnt hold a charge. Shops do make mistakes, This could be one of them. If I'm wrong....fantastic; that's one item off your list to replace.

It is the factory OEM radio. And I still can't get it to work either. I enter the code and all it does is say "WAIT". It "appears" that the antenna is disconnected in the trunk, However, I can't be sure. I don't have a service manual for this thing and can't find one. I'm just going on my years of experience working on Chevy's. I have read up on MB having issues with a start up lock out issue having to do something with the steering wheel. I tried starting it again this morning and couldn't no matter how much I messed with the wires. Then I was messing with the wires and turning the wheel back and forth and the car started. So there is something definitely wrong under that dash.

I assume its a Becker or Alpine unit. Are you sure you have the correct radio code?
If you dont get the code correct 3 times, it'll lock you out and the waiting will display until to resets itself ( if I recall....) I belive you have to keep the power on access until the "----" displays again.
Radios from this time often allow three attempts, each one after waiting 15 minutes. If a wrong code is given a third time, you would have to keep the radio powered on for 24 hours. It needs to be powered, both permanent and switched power active. Easier to take the radio out and run it from a separate power source for the 24 hours until it resets to "----"
If you dont have the right code, then Becker/Alpine or the MB dealer can help.

As for testing the antenna line for continuity, use a test light or multimeter to see if there is a break in the (antenna) line.