RS Motorsport :: Classic Speed Restored

Hi All,

First time poster, looking for some guidance.

Im having a bit of an electrical charging issue with my mk2 RS2000, and i am hoping someone might be able to provide some guidance if possible?.

Up until about 2 days ago, the car has been running and charging no problems. Nothing was amiss, and everything worked fine.

I left the car sitting for a few days and then went out to start it today, and when i turned the key to accessories, i realised that the red charge light on the dash did not light up as it usually does. The car still started fine. I gave it a bit of a rev but really couldnt tell if that made any difference.

I tested the voltage across the battery and realised it was not charging. Voltage was at about 11.90 volts, and dropping. A small rev of the engine whilst watching the voltage meter made no difference.

I thought it might have been the alternator, so i grabbed a spare i had lying around, and fitted it up, but this made no difference. Of course I may have two faulty alternators, but i doubt it.

I put a post on one of the classic ford forums i visit, and one fellow responded saying that if the red light on the dash is not lighting up, then the alternator will never charge. IE: it must close some sort of circuit or something for the alternator to charge. He was suggesting that the alternator not charging is actually a symptom of the underlying problem, and not the cause.

The ONLY things ive done in between two days ago and today electrically was to just loosely fit up a relay wiring for my high beams. I dont see how that would cause any issues though?. All it is is a connection to one side of the high beam fuse, a connection to the positive terminal, an earth, and a + and - to each of the headlights?. Unless Ive blown something whilst hooking it up?............but im not sure what it could have been. All the fuses are fine. I have tested them with my multimeter.

In any regard, I have taken the wiring loom out for the high beam and it still has the same issue.

So anyway, based on all of that, i was hoping someone might be able to help me with some ideas of where i might start. I would be very appreciative.

Many thanks. Merry xmas and a happy new year to you all.

Dave

Howdy and welcome to RSM!

The problem could be simply that the warning light bulb is blown. The alternator requires current to the windings (I think) to provide a charge at low revs. Once the alternator is charging, both sides of the bulb see +12 volts so it goes out.

BTW, you can't replace the warning bulb with an LED type replacement as the circuit won't provide enough current to start the alternator.

Via the dashlight the field-coil in the alternator gets some current to get the charging started.
Check the bulb as mentioned above by taking of the blue wire from alternator and connect it to earth then switch on the ignition-key; bulb should light up.

If bulb is okay, remove the regulator from the alternator. On most type this is held by two screws.
Check the brushes; if they are short then these probably need replacing.

Good luck!

Check your engine earth.

You can hot wire a charge indicator to test the alternator. If it fails that test then replace the regulato or alternator.

Check the fuse box more thoroughly, seeing as you were disturbing it. Look for oxidation, especially if you have the silver coloured fuse material. Check the fuses clip in tight.