94 e320 electrical question - PeachParts Mercedes-Benz Forum

mcdill · #1 09-25-2002, 05:04 PM

A weird thing has been happening to my car lately. While my car is on, the interior lights will turn on and the radio will turn off, and the door locks will not function correctly. It has happened twice. One time while I was driving and the second time right after I turned on the car. In both cases, opening a door and closing it turned off the lights and turned the radio back on. Sounds like a loose wire or short circuit. Anyone have any opinions on the problem?

I just had my battery replaced at Sears. Related?

Matt
1994 E320, 143k

engatwork · #2 09-25-2002, 05:55 PM

Why did you have to replace your battery? I would suspect you have an alternator going out.

mcdill · #3 09-25-2002, 07:10 PM

the battery was dead. the alternator was working fine.

-Matt

mcdill · #4 09-26-2002, 01:53 AM

well, the plot has thickened...

today the car had been acting up even more; the interior lights came on several times randomly, the radio would not produce any sound although the display was on (but the antenna would not raise), and the door locks continued to malfunction. All of these things would happen randomly, but at the same time.

tonight, i went to the grocery store, turned my key to start my car and nothing... except the interior lights would turn on sometimes when i turned the key (doors were shut). because it was dark, i opened the hood and just started wiggling wires and fuses. tried it again and it started.

then to top off my day, i shut the hood, with my tool kit still in the engine bay. remembered a minute later and removed them. then noticed that i had a large amount of antifreeze leaking from my car. so drove about 5 miles home and gave up for the day.

my question is: what the hell is going on? it has to be something electronic, but what would be responsible for such strange behavior? and what about the antifreeze, did the tools cause damage when i shut the hood, or could it be electrically related?

sorry for the long story, i appreciate all of your feedback so far.

Matt

Larry Delor · #5 04-06-2005, 01:50 AM

Hello folks!

After doing a search, I came across this thread....a thread that I wish had some answers, as my 94 E420 is doing exactly the same darn thing.

Has this happened to anybody else since this thread? And, more importantly, has anybody found the cause/solution?

Thanks!

-Larry

zafarhayatkhan · #6 04-06-2005, 09:46 AM

I had the following problem: Central locking not working, no sound from radio, rear interior light not working. Fuse looked good but changed it anyways. Everything started working properly.

The fuses in these cars are open to the environment and they may look good but sometimes stop working.

Larry Delor · #7 04-06-2005, 11:13 AM

Unbelievable! Previously when this happened, it "fixed itself" within 10 mins. (matter of fact, 10 mins after I had left the shop for unrelated work, and had just driven back to show my troubles - when the Tech got in, it problem had magically dissappeared - go figure)

Anyway, I poked at all the fuses this morning and when I poked a red fuse, something clicked...Whaddayaknow! The doorlocks started to work again!

What I don't understand, is if the fuse wasn't conducting current, why would the radio still come on (no sound) and why would the dome light come on everytime I turned on the radio?? That doesn't make sense!

schumi · #8 04-06-2005, 02:35 PM

When my voltage regulator was failing, it caused all kinds of weird electrical problems. I would check it. It takes 30 seconds to remove it (2 screws on back of alternator; disconnect neg. battery cable first) and eyeball the brushes to see how worn they are. It only cost $15 or so to replace. I have also read many times that on older cars you should just replace all the fuses with new ones because slight corrosionyou can barely see can cause weird problems.