Strange electrical happenings....

[Nick Farrow]

Tonight’s update:

Dash is back in and everything is wired up correctly and seems to work. I now have panel lights, the fuel gauge is reading something other than full and the ammeter is connected how it should be. But....I'm still getting the flickering of the headlights when I rev the engine. Also when I rev the engine up to about 2500rpm the ammeter goes mad and starts flicking back and forth frantically.

I put the old dynamo regulator back in to see what would happen and I didn't get any flickering, but I didn't get any charging either...the ignition light was on all the time.

Does this mean that my new voltage regulator is actually faulty (as well as the old one)??

 

[Tom H]

Hey Nick, Good work. YOu found exactly what I suspected. that the lighting cuircuit was somehow wired to the gauges. Good work.

Regarding the light ficker and ammeter jumping , first understand that such behavior is not all that strange. One of the main gripes any of us have had about old generator regulators is that the way they work is by relays (or coils) turning on and off an opening and closing contacts. Normally the contacts open and close quickly enough that you don't even notice any changes, you (and the lights and battery) just see the average current and average voltage. The problem with yours is that this ON/OFF action is "stumbling" .

I suggest you read the whole section in the WSM about the control box. You will probably only understand about half of it, but I'll bet you get a lot of understanding. Fortunately the SV manual contains all the info about the Generator and control box, even tho all SVs had alternators. And I see an especially potent statement in the first para on page 16 of section N describing what looks like your situation and maybe the solution.

http://www.rootes1725cc.info/wsm145/wsm_n/n_16.htm

It's quite likely that your control box, though "New" and unused, may be a long time since it was made and may well have slightly oxidized contacts.


Good luck. I'll bet you'll get it fixed!

Tom

 

[Tom H]

Just to clarify, see the SECOND para on Page 16N.

Tom

 

[Nickodell]

Hi, Nick 1. Could be that the generator brushes are worn down. When that is the case, they start to make intermittent contact with the armature (or more correctly, the commutator). As you speed up the engine the brush springs have a harder job keeping them in contact with the aforementioned.

Nick 2.

 

[Nick Farrow]

Hey Nick, Good work. YOu found exactly what I suspected. that the lighting cuircuit was somehow wired to the gauges. Good work.

Regarding the light ficker and ammeter jumping , first understand that such behavior is not all that strange. One of the main gripes any of us have had about old generator regulators is that the way they work is by relays (or coils) turning on and off an opening and closing contacts. Normally the contacts open and close quickly enough that you don't even notice any changes, you (and the lights and battery) just see the average current and average voltage. The problem with yours is that this ON/OFF action is "stumbling" .

I suggest you read the whole section in the WSM about the control box. You will probably only understand about half of it, but I'll bet you get a lot of understanding. Fortunately the SV manual contains all the info about the Generator and control box, even tho all SVs had alternators. And I see an especially potent statement in the first para on page 16 of section N describing what looks like your situation and maybe the solution.

http://www.rootes1725cc.info/wsm145/wsm_n/n_16.htm

It's quite likely that your control box, though "New" and unused, may be a long time since it was made and may well have slightly oxidized contacts.


Good luck. I'll bet you'll get it fixed!

Tom

Thanks for that Tom!! I'll give the points a clean when I get home tonight and see if that makes a difference. It does sound exactly like the description in the manual. I've got a copy of the Series III manual, but I don't remeber seeing that in it....maybe it's not there!

Something I don't think I mentioned in the previous post is the fact that the temp and fuel gauges are still going up when the engine is rev'd....but the voltage put out by the generator is not excesive...maybe this is just another part of the generator control box issue (or maybe the instrument panel regulator is duff).

Hi, Nick 1. Could be that the generator bruishes are worn down. When that is the case, they start to make intermittent contact with the armature (or more correctly, the commutator). As you speed up the engine the brush springs have a harder job keeping them in contact with the aforementioned.

Nick 2.

I don't think it's the generator in this case as it's a recon unit, but I suppose you never know. It's worth considering if the control box isn't the issue....

 

[V_Mad]

I agree with TomH, and NickOdell has added a credible possiblity too that you need to consider.

Well done for getting this far, you are nearly there. A credit and a good example to the DIY brigade that it can be done!!

The regulator may be an early type. The later ones had more coils to give better operation (current sensing etc). The Haynes Electrical Manual is a good source of info for regulator design and operation.

 

[Tom H]

Nick,

Regarding the fuel and temp gauges going up as the engine revs, it looks like the voltage stabilizer is not doing its job. I see you found it and I'll bet you wired it correctly. Take your voltmeter and measure the voltage output from the stabilizer (or the voltage at the gauge terminal that connects to te stabilizer). Depending on what kind of voltmeter you have - analog needle or Digital- and its response speed, you should see an "Average" of 10 V, but in actuality the voltage will switch from full battery voltage to zero voltage, maintaining a steady Average of 10 V by varying the duty cycle (ON/ OFF time). Since the gauges are slow responding thisi variation is no problem and the gauges respond only to the Average. If you have an analog meter you may easily see the needle going back and forth. On a digital meter you may only see a constant jumble of numbers. I think on my stabilizer the voltage goes on and off about 1 or 2 times per second. If your voltage is stable and steady at Battery voltage, then the stabilizer is stuck in the ON position and no longer doing anything useful. In which case not only are your gauges varying , but they are never correct since they would be getting 12.6 to 14.5 V instead of the stabilized 10 V. You might try giving the case a good rap with a metal wrench or something. May unstick the contacts (notice - contacts - same old technology as in the Control Box. Solid state devices have since made a great impact on electrical reliability in cars!!) )

Good luck,

Tom

 

[Nickodell]

I don't think it's the generator in this case as it's a recon unit, but I suppose you never know. It's worth considering if the control box isn't the issue....

You're right, it is unlikely with a recon unit. However, there's just a faint possibility that for some reason one or more of the brushes are hanging up, either by some foreign object in the brush holder or because the shunt (wire) is snagged. If the problem is in the genny, in a recon one it's more likely to be a loose lead inside. I had that on a new one, once. It sent me crazy until I finally took the thing apart and there it was, a loose terminal inside where it is screwed to the stud that you connect the primary cable to, outside the case.

With electrics, the only way to pinpoint the problem is bystarting at the source and working from there, Sherlock Holmes-style. It's possible to bypass the control box (or fix it temporarily) and test the genny's rated (i.e. maximum) output with a clamp-on DC ammeter, but it would be better to let a pro do that. If the output is consistently as it should, the problem lies somewhere downstream.

 

[Nick Farrow]

OK...time for another update!

I cleaned up the 'points' on the control box, but no joy....same old thing, lights still flickering. You can actually see the tiny blue spark as the box turns on and off.....and this seems to go in time to the flickering. Another strange thing has occured now. I took the car for a little test run during which the wipers suddenly moved a little then stopped. When I got home I ran a test and found that if the engine was running at about 3K with the wipers going and I turned them off, they would keep going. This sounds to me like there is a small amount of current bleeding accross to the wipers somehow; I don't know if this is related to the control box issue or not!

With regard to the gauges, specifically the regulator...does it need to be earthed? I wasn't sure if it did, but when I secured it to the body with a screw it suddely gave a steady reading.

BTW, thanks for all your help so far guys; I couldn't have got this far without you....

 

[Tom H]

easy one first - Yes, the stabilizer needs to be grounded. It's a 3 terminal device and the third terminal is Ground. In think you've found and solved that one. Consider the gauge problem solved.

Wipers coming on mysteriously!!?? Something's miswired or the wiper switch is bad. Set it up so the wipers are going when they shouldn't. Then pull the wire from the wiper switch - the wire that goes to the battery supply. The wiper switch is rated to handle easily much more than 15 volts without "bleeding" across. I'll study the wiring schematic some more later to see if I can see something. And yes, I suspect the wiper and control box issue are related. Douuble check the wiring AND GROUNDS asssociated with the control box. Make sure there is a good ground between the engine and the chassis. There should be a heavy ground strap - a short, bare, braied tinned copper cable mounted near the transmission rear support.It is supposed to make a solid ground connection from the tranny to the chassis. Wihout this or with it making only a loose connection at either end the engine may not be well grounded.

Tom

 

[Nick Farrow]

Thanks for confirming that about the stabaliser Tom; When I took the dash off a few days ago the stabaliser was just tucked up loosely amongst the wiring and when I checked the schematic there was nothing showing it having a ground connection.

I think I'm 90% of the way there now! I took the plunge and bought a new control box from a different supplier and I'm please to say it seems to be working fine. There's no noticable flickering of the headlights or of the ammeter needle. The ammeter seems to read about 15-20 amps under normal driving; I'm not sure if that's correct or not though as I have an Austin 1100 with an ammeter which reads around zero unless there's a lot of load. So the fault seems to be a new but dodgy control box!

There's still the matter of the wipers though. What I can't understand is why there are two wires coming from the wiper motor to the switch (three wires in total connected to the back of the switch, one being the ground). I've checked the schematic for the series 3 and this is correct, but on the schematic for the series IV there is only one coming from the motor. My point here is that I took one of the wires off the back of the switch and the wipers still worked (and didn't move after the switch was turned off). When I touched the now detached wire against the chassis I could see a small spark, so obviously this wire is live (although you might expect it to be as it's connected to a switch). Is there a reason for this extra connection? I thought it might be for the self-parking circuit, but even without it the wipers park fine!

Nearly there though!

 

[tony perrett]

Are the wipers on Series 3 two-speed?

 

[Nick Farrow]

Are the wipers on Series 3 two-speed?

Mine certainly are - and both speeds work with just the one wire attached.

 

[Tom H]

Nick,

The two wires to the wiper switch are, I assume for two speeds. I cannot figure out what the English schematic is telling us about the switch action, but I am sure that it is inmportant to get the wires connected to the proper terminals. If the wires are connected to the wrong terminals all sorts of strange things can happen. I'm guessing that as wired now, you do not have a two speeds on your wiper motor, which would confirm miswiring.

Regarding the Ammeter, once on the highway and after running for 20 min or so the ammeter should be reading about zero, indicating that your battery is about fully charged. I am not 100% sure that SIII wiring is the same or similar to SV wiring, with an Alternator, but in the SV I am 100% sure that the ammeter, if wired correctly, should indicate the current going into or out of the battery. So once charged up, and running on the highway, the ammeter should read about zero, inddicating nothing going into or out of the battery. In that mode, the generator is supplying all the current the car needs. since the battery is fully charged it needs no current going in to it and since teh generator is runningand supplying all te current the car needs there is no current coming FROM the battery.

I suggest you stop the car , turn off the ignition, and turn the lights ON. The ammeter should read neg, indicating current coming from the battery. If not, it's not wired correctly.

Nice work so far,

Tom

 

[Nick Farrow]

Nick,

The two wires to the wiper switch are, I assume for two speeds. I cannot figure out what the English schematic is telling us about the switch action, but I am sure that it is inmportant to get the wires connected to the proper terminals. If the wires are connected to the wrong terminals all sorts of strange things can happen. I'm guessing that as wired now, you do not have a two speeds on your wiper motor, which would confirm miswiring.

Regarding the Ammeter, once on the highway and after running for 20 min or so the ammeter should be reading about zero, indicating that your battery is about fully charged. I am not 100% sure that SIII wiring is the same or similar to SV wiring, with an Alternator, but in the SV I am 100% sure that the ammeter, if wired correctly, should indicate the current going into or out of the battery. So once charged up, and running on the highway, the ammeter should read about zero, inddicating nothing going into or out of the battery. In that mode, the generator is supplying all the current the car needs. since the battery is fully charged it needs no current going in to it and since teh generator is runningand supplying all te current the car needs there is no current coming FROM the battery.

I suggest you stop the car , turn off the ignition, and turn the lights ON. The ammeter should read neg, indicating current coming from the battery. If not, it's not wired correctly.

Nice work so far,

Tom

Re: the wipers; it seems I'd wired them up wrong! My S3 schematic was very blurred and the numbers were unreadable, so I used a series IV schematic to wire it. After a stroke of luck I managed to find a non-factory schematic on the web which allowed me to wire them up to the correct terminals....sorry, that was just me being an idiot and thinking later ones would be similar!

Re: the ammeter; it's wired in series between the soleniod and the control box connection A (I have removed the old direct connection between the solenoid and control box). Until a few minutes ago turning on the lights was having no effect on the ammeter. This caused me to re-examine what was going on and I discovered someone had wired the headlights directly to the solenoid instead of to the control box terminal A1. Now when I turn on the lights with the engine off the ammeter drops to about -15A. The battery I have in the car was pretty flat this morning (TBH Ive got no idea how old it is, so it might be past it's best even though it looks new), so that might explain the large amount of current going in to it.

 

[Tom H]

Nick,

Sounds like the ammeter is wired right. I AM a bit puzzled about terminal A or B. I see that the control box in the SII scematic has a terminal A. And when I look in the SV manual to see more details about the Control box what Terminal A is , I do not find terminal A, but rather Terminal B. But I assume they are the same.

Looks like you are getting it all together. Your SIII is a beauty.


Tom

 

[Nick Farrow]

On the S3 you have A1 A F D E. From what I can see (but I might be/am probably wrong) A1 is power out of the box to the light circuit and ignition switch; A is power in from the solenoid and a junction for the power to the fusebox fuse 2; F is the 1st connection to the dynamo/generator; D is the 2nd dynamo connection/ignition warning lamp and E is the ground connection.

Going to take the car for a test run today and see what happens....I hope everything is fine now, but the proof is in the pudding! I'll let you know later how it's been.....

Thanks very much to Tom H, Nickodell, V Mad, Tony Perrett and everyone else for your input. I couldn't have done it without you! It's great that an online community like this exists and I hope in future when I know the car a bit more that I might be able to return the favour....

Cheers!!

Nick

 

[Nick Farrow]

OK...been for a long drive today.....probably did about 100 miles in total! The weather was absolutely gorgeous and once you get behind the wheel with the wind in your hair it's hard to stop!! I can report there have been no adverse electrical happenings today. The fuel gauge I know is working as it dropped with fuel useage and the temp gauge is working as it rose steadily to a healthy 170 deg and stayed there, rising minutely in traffic etc. The ammeter once cruising seems to read about 7 amps; it doesn't really get as low as 0. I don't know whether that's a bad thing or not, but I can live with it if it's not damaging anything!

It's funny how you solve one problem, then another comes along straight away! I now have a tapping coming from under the car, which I'm pretty sure is the exhaust where it passed through the cruciform memebrs, so don't be suprised if I'm asking more questions soon....

Thanks again to everyone who helped me on this one!