87 190e/w201 Perplexing electrical problem: No Power
 

Hello,

I've just developed a perplexing electrical gremlin in my 1987 w201 190e, which in, in short, an issue of No Power

As I went to start my car, the electrical power died in my vehicle. I inserted the key, and turned to position 1 through start, and a split second prior to starting the electrical power left the vehicle. No lights function, no radio, no headlights, no domelights, no turn signals, no buzzer. No electricity. No solenoid click, no starting. Silence.

The power locks function (I have no idea how those are activated anyhow). When I remove the key, close the car, and re enter the vehicle, the dome light has power as the door is opened.

When i turn the key to any position, i recieve NO power and the dome light ceases to turn on, either by its switch or the switch on the door. It I operate the dome light switch before turning the key, that also causes the power to fail.

it seem to return after a while of not touching anything and closing the door. In essence, whenever I activate any electrical component, the power immediately ceases in its supply.


Is my problem a starter switch problem? To me it does not seem to be the case. Can i test the switch without removing the steering wheel, etc? Can you tell me the location of any relays that may have failed? I do not know their location on this car.

Since it is dark, I can do nothing, but later today I am planning the folowing steps:
Ensure battery is healthy. My "guess test" is that it is, but I will take my meter to it tomorrow.
I will inspect and replace the fuses.
I will remove the kick panel to check for loose wires. The kick panel came unscrewed recently.
I will inspect the lock cylinder by removal, as a just in case guess since it takes 2 minutes to remove and replace.
I have no other ideas.


Would anyone care to give me some extra hints? I have never encountered a problem just like this before. My apologies for the long description, my intent is to be thorough.

Bad battery. Has just enough juice left to light the dome light briefly without any other electrical consumers on, but the moment the key is turned, there's not enough to even light up the gauge lights, never mind to spin the starter. Power door locks work because they are vacuum-operated, not electrical. Take the battery to get it tested to confirm. While you're replacing the battery, take a moment to clean up the connectors on the battery cables and the ground connection. If the battery is relatively new, you'll have the additional problem of troubleshooting the reason for it being drained. But if it's at least 5 years old, it's run out of life. Welcome to the forum.

To add to that, check out the alternator too. You will be glad you did.

sound advise
 

Alternator ;The least replace the regulator bushes or the regulator itself. i assume it will have worn bushes.
mak

Actually, it was a break in the negative terminal battery cable. The break was inside the insulation. The ground connection is otherwise solid. It came apart when i was roughening up the surface a bit with a brush. This yet another reminder to me from an inanimate object: Be more thorough!

No surprise to you all, then :)
The battery is still strong. the alternator produces a charging current. I'll still take a look at the bushes and regulator tomorrow. The alternator is (my guess here) 6 years old.

Thanks incredibly for the tips (and not knocking me :). Forums like this are absolutely indispensable.

Look at the positive battery connector - there should be an outboard connector -make sure this connection didn't vibrate loose.