Sometimes it charges.... Sometimes it doesn't!

[markpink]

I have early model 1977 124.

I have had the car for two months. For most of that time, the charging system seemed to be fine. Now sometimes, the red "Hey I am not charging" Light comes on and stays on. And sometimes, the light goes out after I start the car and every thing is fine. There is a short or loose wire here somewhere. I could replace the whole alternator, but I am not sure that is the problem. Are there any places I can look for a loose connection?

THanks


Mark from NH

[rlux4]

Does it come on full brightness, or dimly. It is not uncommon for these to glow dimly under full load, but it's not a cause for alarm. If it's coming on full brightness under less than full load (lights, wipers, heater fan) then you should check the output of the alternator to see if it is fact not charging as a first step. Most of the auto parts stores will run a free check on your charging system also.
Ron

[manoa matt]

Some times the light may come on while idling because the alternators typically have a cut in speed of 1000, or 1100 RPM's Pulley size sometimes may influence the speed of the alternator. The local chain auto parts store should be able to perform a simple free diagnostic check without removing the alternator from the car.

[markpink]

I know it was not charging, because everything went dim when I was driving home from work on Monday. I was able to get off the highway and ended up buying a new battery. New battery was fully charged, I drove home.

The light was bright when it was one.

It turns out the fuse for the voltage regulator was the issue. Actually not the fuse but the contact. The fuse was good but not making new contact. I already bought a new fuse box , a few weeks ago. So I need to put the fuse box to the top of the fix or replace list.


thanks


Mark from NH

[manoa matt]

Before installing that fuse box, clean all the contact surfaces well and put a little dielectric grease on them. Then lightly bend the fuse contacts so that when the fuses are installed they are clamped securely. If the fuse is not held securely the wire is likely to burn up without blowing the fuse first. I speak from experience.

[mbouse]

The local chain auto parts store should be able to perform a simple free diagnostic check without removing the alternator from the car.

wish that were true around here. it is not necessarily true. Auto Zone here will only test OFF the vehicle, then are clueless what to do with the exciter circuit....their machine can't handle an alternator that old of a design. they can sell a refurbished alt, but not test what they sell.

i recommend finding, then getting to know the local alternator/starter rebuild guy. he'll be happy to test your alternator (correctly) for free, if you take it off the car and take it to his shop.