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Did you try this:
Measure voltage at B+ terminal of the alternator if not battery voltage replace Batt fuse in engine bay.
If not battery voltage measure voltage at B+ test point S terminal on alternator; if not battery voltage replace "Batt" fuse.
If battery voltage at B+ and S, turn ignition to run position and test for voltage at terminal L of alternator. If voltage is not greater than 1 volt check wiring to alternator and globe in battery warning light and circuit between warning light and alternator. If greater than 1 volt check or replace regulator.
 

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And how is the battery warning light behaving noting my advice on page 1 of this thread vis:
If an alternator positive diode has shorted the battery warning light will not go on in any key position. If a negative diode has failed the battery warning light will slowly dim as engine revs increase. The slip ring can also ground - you can check by removing the plug in regulator and checking with a multimeter the resistance between the slip ring and case ; it has to be 200 ohms or more.
 

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Discussion Starter #23
Yeah done all that. I got 240 ohms n the alternator. And to check the amp drain i disconnect the negative. Put the meter on the negative lead and the neg terminal.
 

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Discussion Starter #26
Yeah blue, I had to take the coolant reservoir off to access those relays but yeah I did check them and the drain is still there.

I'm pretty desperate and taking the car to an auto electrician tomorrow. If that fails, its going up for sale.
 

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Discussion Starter #28
Hey blue,

I did try this before and the battery light did come on but I just tried something just now in my driveway. I turned the key in all positions and it seems that my battery light is not coming up at all. So according to MU's advice, the positive diode on my alternator HAS shorted. What happens next? How can I make 100% sure that this is actually what's draining my battery?
 

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How can I make 100% sure that this is actually what's draining my battery?
Only by swapping alternators or by dismantling the alternator and checking the diode pack with the diode setting of the multimeter. But if you disconnect both wires from the alternator first (disconnect the battery first so you don't damage the alternator) and do your ammeter drain test that should tell you if it is the only or major drain point.

Also while you are at it, check the large yellow wire that goes between the alternator and battery has not gone brittle at the alternator end and frayed inside (because of the proximity to the exhaust manifold and the adjacent heat this often happens). If the wire is stiff and has discoloured insulation it will be brittle and frayed inside and will need replacing. While this won't directly cause your parasitic battery drain, it will often cause diode failure. If it needs replacing use a wire of equal or (better) greater gauge. It is best to cut it off about 10 to 15 cm from the alternator (to the point where it is flexible and normally coloured) and it's a good idea to either use two (2) hi amp Anderson connectors like this http://www.altronics.com.au/p/p7817-75a-red-high-current-dc-connector/ or a circuit breaker like this http://www.altronics.com.au/p/s5881-150a-panel-mount-ip67-waterproof-circuit-breaker/ to join it to the old wire (and it saves having to disconnect the battery next time you need to work on the alternator) with an eyelet terminal at the alternator end. Jaycar and most car audio specialist also sell these bits.

And yes it's not unusual for the light to come and go when the diodes fail. It seems there is often enough capacitance in the system to store enough power for it to act like a small battery and power the light after engine has been off for a short time.
 

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Discussion Starter #31
Shit, I dont have a spare el fairmont alternator lieing around. As for the ammeter drain test, I'm not confident I did it right the last time. Could you perhaps tell me whats involved? step by step, i'm a rookie when it comes to electrics.
 

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Could you perhaps tell me whats involved? step by step, i'm a rookie when it comes to electrics.
Follow the steps under "computers that must time out" section here Testing for Battery Drain - Randy's Repair Shop and do it before you disconnect the alternator and after. I'll bet the alternator is the culprit though that lack of a Battery warning light engine off key in run position is a giveaway.
 

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Discussion Starter #33
When you say unplug the alternator, you mean the black plug? or do you mean the black plug AND the white wire too? The battery light is definitely not showing up on my cluster at any time.... ever...
 

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Discussion Starter #37
Hey blue,


thanks for all your help mate. I bought a second hand alternator this morning and just fitted it in now. Nomore 3Amps drain. Only draining about 0.08Amps now which is apparently perfecto.

I appreciate all the responses to help me sort this out.

thanks again
 
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