89 300se ignition switch electrical portion - PeachParts Mercedes-Benz Forum

bolomiester · #1 05-10-2009, 01:30 AM

My 89 300se has begun to stall shortly after being started, then when I turn the key to restart it does nothing, no dash warning lights, buzzer or anything. It's like the battery fell out. Then in minute or two it will be fine. It happened the first time a few days ago, then twice yesterday and twice again today. Could this be the electrical portion of my ignition switch failing, or some other likely suspect? Sure is scarey. The key part works fine.

If it is the electrical portion of the switch, can anyone tell me how to change it?

Arthur Dalton · #2 05-10-2009, 06:07 PM

First check would be the battery cable terminals...

Put On the headlamps and then try the key..if the headlamps go out, the terminals need cleaning.

ps2cho · #3 05-10-2009, 06:39 PM

As Arthur said, clean the terminals then check voltage at the battery. You may also want to consider looking at the negative cable as over time the wires inside can fall apart or even sever completely. It happened to my 300TE about two months ago.

bolomiester · #4 05-15-2009, 11:08 AM

The cables are good and tight, and the negative cable is solid, showing no corrosion. However, just to be sure, I removed both cables from the battery, cleaned the connectors and battery posts, applied silicone dilectric grease and tightened them again.

It seems that now it's always taking at least a couple of tries to start, even from cold, and when it does start it stumbles and sputters for a bit before smoothing out to a normal idle.

Last night I drove about 30 miles and as I was parking the car it stalled. When I turned the key to restart, it was the "totally dead" thing again. No warning lights on the dash, no buzzers and of course no cranking from the starter. I kept trying to restart about every 30 seconds for 4 or 5 minutes, but with the same dead results. Finally, I got out of the car to see if the headlights were on, (daylight and raining), and they were. When I got back in, everything was back to life and it started as it always does, several trys to get going, then spit and sputter for a bit, then settled down to a normal idle and ran fine.

Arthur Dalton · #5 05-15-2009, 12:51 PM

Give the fuses a spin in their holders ...

bolomiester · #6 05-15-2009, 04:30 PM

MYSTERY SOLVED!

I took the car out this morning & experienced the same thing I have been. Took 3 times to start, then bucked & sputtered for about 30 seconds before smoothing out and running fine. A few hours later I was going somewhere else and everything was absolutely DEAD! No dash warning lights, no buzzers, no headlights, no crank, nothing.

I used a multimeter to check the battery voltage. 12.88 volts, then I hooked one end of a jumper cable to the negative side of the battery and the other to the body. Still dead. Then I spotted the smaller wire that is nutted to a stud on the positive battery cable connector. Somehow I never noticed it before. The nut was not even finger tight! I tightened it and everything came back to life! Started on the first try, idled smoothly right away.

I traced the wire to where it terminated in a junction block on the inner fender, popped off the cap and saw that there was a little corrosion on the 2 posts and nuts.

Anyway, I took it all apart, wire brushed all the corrosion off, bought new stainless steel nuts, washers and lock washers, coated everything with silicone dielectric grease and put it all back together.

It now starts first time everytime, and idles perfectly right from the get go.

Life is good again!

Another thing that was apperently related was something odd in the climate control. It had started putting out cool air from the side vents when I needed heat. Now the side vents are warm again.

Hard to believe so much trouble from a loose 6mm nut.

Arthur Dalton · #7 05-15-2009, 04:35 PM

That is B+ for the car .which is why I had you try the headlamps. The heavy bat cables only feed the starter.

bolomiester · #8 05-15-2009, 10:36 PM

It was the headlights that threw me the curve. Except for last night the stall/dead thing always happened where I was blocking traffic. In those cases it came back on in 1 or 2 minutes. Yesterday was the first time I wasn't in everyones way and it took much longer before it came back to life. It was was daylight though I was using the headlights because of the rain. After it stayed dead so long, I got out to check the headlights and they were on. Then when I got back in it started right up.

Today was the first time it ever went dead in the garage. I was so glad as it gave me the time and tools to figure out what was really going on.

Thanks so much for pointing me in the battery direction. Because of the headlights being on last night I was convinced it couldn't be battery area related.