suntubi

I was recently driving my '89 300 E at night and noticed that the radio was cutting out when I stepped on the brake or when the turn signals were on. The power windows cycled very slowly so I knew I had a power problem. What worried me most was getting the car home and then looking for the root of the problem. Of course, the car won't restart but I have power enough to run the radio and interior lights ( very dimly).

I suspect an old battery no longer able to hold a charge but should this have caused the radio cut out during driving or the windows to cycle slowly?

Any opinions on what really is going on here?

Jer

I would say "yes." The radio contains microprocessors and other ICs which need a minimum voltage to operate. If the charge failure lamp has not come on, just replace the battery.

suntubi

Thanks for the advice. Are there any resets, say on the radio, that have to be done once I disconnect the power totally?

Gordinho80

if it is fcatory, most have a security feature where you have to unlock it...4 digit number usually available at the dealer...

one thing you might want to look at too, your alternator...

the electric system of a car works like this...battery to start car and run direct power supply to it all, alternator to charge battery as car is running...

jump start the car...let it run for a couple of mins with the other car still connected...

then disconnect the other car and while your car is still running, disconnect the Negative terminal from your batter completely...if your car dies...alternator needs replacing...if it runs for a little, even a little rough...alternator is fine...

just my 2 cents as i've replaced the alternator and battery in my 93 300D 3 times already in the past 5 years....i guess that is what you get when you run a 3000 watt stereo system with a cheesy 70 amp alternator...

suntubi

Well, I got back to working on the power problem and after the car would not start when I parked it one night, it did start repeatedly the next day.

I had a service call on the car and the battery showed it was fine and the alternator was putting out 14 + volts. But this was with the alternator attached to the battery in the car -- the simple test. But with the car running and all the electrical devises on, the engine didn't miss a beat. However, the radio popped whenever the turnsignal cycled.

Any one know whether there are other demons at work here?

(Just to get by I bought another battery and it is in the trunk until I can get a solution or get it to a shop.)

suntubi

I just got through driving my problem child from Chicago to New York without a problem. MPG hurt a bit as I set the cruise at 78 - 81 and went all night. 18 - 19 mpg without as much as a hiccup.

All in all about 900 miles.

What a nice ride -- it's no SEL but it has its own nice feel.

I did take one precaution, I bought a spare battery at a Walmart before I left Chicago -- just in case I had to limp off the highway. I hope Walmart will let me return it!

It's amazing what these teenager autos can still do.