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non-charging issue: alternator or regulator or wiring?
This should be fairly straightforward, however the more I look into it, the more confused I get about it.
I picked up my car after an extensive interior rebuild and lo and behold, the electrical system was not charging. Because I did not want to diagnose by randomly replacing parts, I tried troubleshooting to no avail. I still can't pinpoint if it's the alternator, regulator, or wiring. The wiring diagrams are causing more confusion than help, since not only were the early S1 cars different from the late ones, but my wiring colours are now all a lovely shade of brown. To complicate it further, my car originally had a steering column lock, but I had that removed years ago (the wiring diagram shows that to be different from the non-steering column lock).
My car is a 4.2 S1 FHC, built in early 66 (RHD). The alternator was replaced a few years back; the wiring and the 4TR are original. Because the alternator was replaced and is unmarked, I'm not convinced the wires are going to the right places and it's impossible for me to tell where each wire goes. The regulator does have its markings, but the colouring on the wires is no longer visible. In addition, the wiring harness to the regulator has four Lucar connectors, whereas the regulator only has spades for three.
Is there a way to tell what wire should be going where? I have only a very basic multi-meter and not much expertise in using it. Any suggestions would be appreciated.
Can you please clarify a couple of things to help diagnosis? The alternator was replaced years ago. Did the system work OK afterwards? Is the charging problem new? Also, what does not charging mean? Forgive the question, but it could mean the battery runs flat, or it could mean the ammeter doesn't show charging. Make sure your multi-meter is on DC volts, what is the voltage across battery terminals when car is switched off? If the car starts, what is the voltage across the battery terminals when engine is running? Hope this helps get the diagnosis going! Cheers, Dave
The alternator was replaced about 4-5 years ago, but the car has seen very little usage in that time. After that, the ammeter fluctuated around, and the reading became unreliable. So I would say that no, the system wasn't OK after that, but it wasn't non-functional either.
The non-charging problem is new, however. The ammeter shows a slight discharge when running and more of a discharge when additional loads are placed (lights, fans, etc). My auxiliary voltmeter starts out at 12.7V (after the battery has been trickle-charged), and drops to ±11.4V after an hour of road time.
Voltage across the battery is ~12.7 when fully charged, and drops slowly as the car runs. The battery is about 5 years old and is ready to be replaced, but it still holds a charge.
I've already ordered a new 4TR unit and I still have my original 11AC. I'm wondering if the problem lies in the wiring--that somehow, something got mixed up at some point.
There should be 12v at the alternator large terminal (left on your photo).
The grounding that CoolCat suggests at the 4TR, is equivalent to grounding the Field terminal (bolted wire on the right). This would put the alternator to max output and should be visible as an immediate rise in battery voltage.
Mucking with the other terminal (bit of red showing) should alter the indicator light I think (with engine not running, just to check continuity).
BTW - Do you have a wiring diagram? Here's a link to one on this forum (hope it works). I think its the right one, but please check its appropriate for your car - there's a VIN number guide at the bottom.
You mentioned four connectors to the regulator in the harness - that's got me confused, but the diagram might help identify the wiring even if the colors are not clear any more. One trick to chasing wiring issues like this is to disconnect at each end to isolate that wire and see if the wire has continuity. If not, then it might be broken, or the connector isn't where it should be.
Yes, that's the wiring diagram that I've been using, however I don't know if I should be following the basic one, or the "alternate circuit for cars with steering lock".
In either case, I've identified the following:
I have 13.1V across the battery.
On the regulator, the (-) has continuity to ground; the (+) has continuity to the wire next to the 'B-post' on the alternator; and the (F) has continuity to the wire (with the bit of red) on the alternator.
There is no power to the (+) lead on the regulator (marked with blue tape).
Bypassing the 4TR did not yield any change.
The large bolted wire on the alternator has 12V (actually 13.1V since the battery is fully charged).
The only relays I can see are the two on the left wheel well. I am assuming the top one is for the horns and the bottom one is the 6RA for the charging circuit. However, the basic wiring diagram isn't showing how a 6RA relay is connected to the circuit. The regulator (+) lead does not seem to have continuity with the relay.
The ignition warning lamp lights up when the ignition is switched on, but once the car is running, does not light—even at low RPM.
I think the black wire on the alternator that is farthest from the others goes to the 3AW relay/ignition warning lamp, but that is just a guess.
I cannot find where the 3AW relay is.
More pix attached. Additional thoughts?
the regulator with the four leads. I added the color tape to temporarily identify. the two relays on the left wheel well. the bottom relay. is this the 6RA relay?
(Apologies I mixed up F- and AL alternator terminals above)
To recap you've got Field F- (red bit) continuity between alternator and 4TR.
You need 12v at the F+ terminal (next to the big wire), which also goes to the 4TR + terminal. And that's supplied by the 6RA relay.
Although the upper relay says 6RA, the lower relay has braided wires like the alternator/4TR so I'd check for some continuity there to F+ and 4TR+. Or test that relay, I'm not sure which terminal is which but 2 are the coil and 2 are the switch. Likely the relay, which supplies the 12v you're missing.
I'm working from the coolcat diagram on Page 2, much easier to follow.
It's still very confusing. The system is definitely not charging at all, yet the ignition warning lamp goes off as soon as the car starts (the ammeter goes to slightly negative and the battery gets drawn down from).
@Valerie: thanks for the pix. If I have a 3AW relay, it's definitely not in the same spot as yours.
@Dave: the wiring diagram seems to indicate that my car uses the alternate circuit for cars with steering column lock (which my car originally had) because there is no 6RA relay on the non-steering lock cars. Perhaps no relay is needed?
@Chris: the CoolCat diagram differs from the 'official' wiring diagram in that it shows a 6RA relay being used, whereas the factory diagram does not (unless it is for a steering lock car). I'm wondering if the CoolCat diagram is not for the later 4.2 cars. In addition, for the 'steering lock equipped' cars, the two diagrams have the W1 and W2 leads on the 6RA relay swapped.
The (F+) lead at the alternator is getting 0.0V. This seems to indicate that the 6RA relay is DOA but maybe it's the wiring.
My questions are now:
which wiring diagram should I be following? The factory diagram does not show a 6RA relay and therefore conflicts with the CoolCat diagram. Or since my car originally had a steering column lock but no longer does, is the alternate circuit diagram still correct?
is there a way of bypassing the 6RA to see if that is the culprit?
where do the 6RA W1 and W2 connectors go? Or is it even in the circuit (per the factory diagram)?
does the 3AW relay have anything to do with the actual charging, or is it merely for the warning light (and can therefore be discounted in my troubleshooting)?
Ok, let's see if I can sort this out for you. First of all, the CoolCat diagram applies to late 4.2's with a 3AW relay, which would not include your 1966. For the early 4.2's, the indicator light is operated by an oil pressure switch, which is located on the right side of the engine block.There won't be a 3AW. It may sound crazy, but the ignition light on these cars has nothing to do with the alternator or the ignition system. All it tells you is that the key is on and the engine isn't running. It's a crappy design, but praise Lucas..In all other respects, the '66 wiring is the same as the later cars. Your car does use an alternator relay, and there is a relay on the official parts diagram. The 11AC system can't work without one.
Since your car won't have a 3AW, it shouldn't have any wire on the alternator's AL terminal, but it does. I'm assuming that this ends up as the loose connection next to the VR. If that's correct, it's a problem waiting to happen. You need to disconnect it at the alternator, and tape off the ends for safety. I would guess that someone bought the later alternator harness.
To find this problem, turn the key to the "run" position. Then set your meter to DC voltage and clip one leg to any good ground. test the "+" wire at the VR, which should have 12.something volts. Then check the wire on the alternator between the B+ post and the red wire. That one should also have 12.something volts. I'll bet that you don't have voltage in either location. The likely culprit is the alternator relay, which is the second from the top on the left fender apron. The one that's "made in Taiwan". These relays have a bad reputation in service. SNG carries Lucas branded relays in a green box. They work pretty well.
@mxfrank: I don't doubt in the least the crazy bits in the wiring (I recently learned that the factory heated rear window is wired to be on with the ignition--no on/off switch). So even though the factory wiring diagram shows a 3AW relay, it's not really on the car itself. Actually, it looks like I should be following the alternate circuit for cars with steering column locks (which shows the 6RA relay in place and no connection to the AL lead). The harness is original, but a new connector was fitted when the alternator got replaced over 3-4 years back.
There is no power at the regulator (+) lead or at the alternator (F+) lead. Also, the alternator (AL) lead does lead to the other end of the mysterious non-used 4th connector at the regulator. I'm assuming that the recommendation is to replace the 6RA and to leave the (AL) lead disconnected.
Does it make sense for me to add the 3AW circuit back in at some point, or is that just asking for more punishment?
Can you tell me which wiring diagram you are using? Is it the one in the Bentley manual, the Haynes manual, one of the ones on the my site or something else? It would be easier if we were looking at the same thing.
My recommendation is to not worry about a 3AW. It serves the same purpose as the pressure switch, and tells you almost nothing about the state of the charging system. What you have is working, let it be.
Your problem appears to be in the relay or the relay wiring. You can check to see if you have 12V at the relay. If you do, replace the relay. DO NOT attempt to run without the relay. The reason it's there is to power off the alternator field when the car is shut down. If this circuit is connected all the time, the least you would be risking is your alternator and VR. At worst, enough heat could build up to start a fire.
I'd be curious to know whether the loose wire has continuity with the wire plugged into the AL terminal. In any event, I would disconnect that wire at the AL and either remove the ring terminal or insulate it with a bit of shrink wrap.
Just a quick guess. I can't be sure of the harness wiring because the colors are faded and dirty. But the relay should be wired as follows:
C1: unswitched 12V+ it will have power whether the key is on or off (Brown/Red)
C2 should have two wires, one goes to the alternator F+, the other to the VR + (Brown/Purple)
W2 Should be a ground wire (Black)
W1 switched 12V+, it will only have power when the key is on. (White)
Given the poor state of your wiring, you will have to verify the wires with your multimeter.
The wiring diagram I am using is attached. I think it's the same as the Bentley service manual (my copy of that is off-site, plus it's easier with a print-out of the jpg).
The wiring seems to check out; I've traced the following:
W1 is getting 12.7V (with IGN switched on); no power (w/ IGN switched off)
W2 is connected to ground
C1 is getting 12.7V (unswitched)
C2 wires have connectivity from alt (F+) to reg (+). [weird side note: my multi-meter did not show connectivity when I tested the Lucar connection at C2 to the individual points, but did show full connectivity when I tested (F+) to (+).] [I then used jumper wires to bypass the original wiring of C2---(F+) and C2---(+). Still no charging.]
You are getting better help than me, but anyway...
You appear to have that relay with 12v there (and is directly connected to the alternator F+, or should be). I would be thinking, who cares what's "further upstream" in the dark recesses under the dash if you have 12v at that relay. You could just jumper C1 to C2 and get charging (if the relay was faulty).
The other side, F-, is where the regulator is. That could be jumpered to ground to prove charging.
I have to say, as an electronics technician, a majority of problems are "faulty connections", and some of yours don't look too good. Clean them as best you can, or even plug-pull plug-pull, before worrying about what it's connected to!
Now, all you guys & gals love the E-Type because of it's shape. But I love this 60's car because it has electomechanical gizmos and bi-metallic flashers & things. Compared with my current XJ, where I can't do a thing without spending 500 bucks on a computer diagnostics machine, it seems easy. (and I'm a retired computer geek, in 10yrs of retirement everything changed again)
fvc496, you seem to be really close to solving it and in my opinion are a dab hand with a multimeter. Just those connectors look suspect...on the inside.
Well, I've done what I hoped not to do, and that is replace all of the items to 'figure out the problem.'
New 6RA relay ("Lucas' branded from SNG) installed: no charging.
New 4TR regulator tested: no charging
My next step is to replace the alternator... I'll report afterwards.
@ ChrisMills: I'll agree, it's the difference between analog and digital. And something analog breaks, at least you have the chance of fixing it. It's hopeless if it's digital.
Reporting back on the non-charging issue. As it turns out, all of the components were functioning correctly, but the wiring was creating the problem. I took the car to my mechanic and it took him a day and a half to find the issue (after pulling the alternator, having it bench-tested—twice). He ended up checking the continuity of everything (I thought that I did that, but obviously I missed something), and ended up replacing the connecting lugs. The ammeter is a bit jumpy now, but at least it's working and my voltmeter is at 14.4 volts when running. Looks like Chris Mills was right!
non-charging issue: alternator or regulator or wiring?
