Hi everyone I hope someone on here can shed some light on my troubles. I have a 1986 240DL wagon. The charging system was not working so I replaced the Alternator ... now it shows charging BUT, at idle I have the charge indicator light on and also when it glows dim so does the parking break light ..... giving a little rev in RPMS makes both lights go out .... as stated, the system shows 14.3 volts at the battery ...... the battery is 1 year old .. any help would be very much appreciated.

Thanks in adavnce,
Dave

 

If the alternator is new and good, just a couple of obvious things would be

1 is the battery ok?...clamps snug?

2 is the alternator belt snug enough?

After that I think its ground wires.

 

Battery seems fine as it is holding a charge but has been dead several time from charging problem before replacing alternator.

Belt is tight and no slipping or noise.

As far as grounds I looked everything over and seems all grounds are good.

What would cause both the charging light and parking light to glow till rpms are raised something has to be a link in that ...... this one is a puzzle but I am sure someone will have input taht figures it out.

Thanks for your good ideas .

Dave

 

A very low idle?

Mine was flickering last week too, I changed the brushes and its good now.

Maybe when you installed the new alternator you didn't get the ground wire quite right,
theres a small wire which comes from the rear of the alternator to the intake manifold(?)
I believe thats critical.
What other wires did you disturb?
the positive lead?, I'm not good with wiring , what do you get out the back of the alternator vs battery?

When the lights are flickering, whats the voltage output at the alternator,
then take a reading at the battery also with the charge light flickering.

Is anything else turned on?

Pulley tight ?
Crank pulley good? (they CAN slip).


After all that, it usually turns out to be some oil soaked cable terminal ...judging by everything I read.

Typically near the starter.

 

A very low idle?
Idle is a little low but rpm needed to shut light off is 1100

Mine was flickering last week too, I changed the brushes and its good now.
New Alternator

Maybe when you installed the new alternator you didn't get the ground wire quite right,
theres a small wire which comes from the rear of the alternator to the intake manifold(?)
I believe thats critical.
What other wires did you disturb?
the positive lead?, I'm not good with wiring , what do you get out the back of the alternator vs battery?
I made sure the ground was attached to the alternator otherwise only the B+ and one other is used

When the lights are flickering, whats the voltage output at the alternator,
then take a reading at the battery also with the charge light flickering.
14 at the battery I have not check the rear of the alternator

Is anything else turned on?
No other draining items on at test/idle time

Pulley tight ?
Crank pulley good? (they CAN slip).
Crank pulley is tight


After all that, it usually turns out to be some oil soaked cable terminal ...judging by everything I read.
No oil leaks in that area ... motor does not have any leaks (at this time :&gt ))

Typically near the starter.

 

Its a new alternator, the brushes could still be seating.

The output measured at the alternator should be 14.4v

From the FAQ
"
[Symptom: idiot lights all go on; also, oil pressure gauge is erratic:] Having all the idiot lights go on at once is not as strange as it might seem. This will happen if the small wire leading to the back of the alternator is grounded. It will also happen if the alternator is not generating any current. When this wire is at ground potential, it is the same condition as before you start the car - hence the idiot lights are on so you can check they are not burned out. The wires for the alternator and also the o/p sender go around the front of the engine under the main crank pulley. (If you get under the front you will see what I mean.) Dripping crank seals often get oil all over these wires. Not to mention it is hot by the alternator. Flaky insulation may be at work. If you really want, you can reroute these wires around the right side of the car instead and splice into the harness at the firewall.
"