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TR2/3/3A Ignition Light On

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frankfast said:
...have ordered a cleaned and adjusted one from Moss. If the one I remove can be bench tested and adjusted, I will try that. It would be nice to have a spare.
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A spare is good, I carry one on long trips. There are two styles - the early one clamps the wires with screws, the later uses Lucar (spade) connectors. Either can be made to work but easiest to have the correct style for your wiring harness.

I have never adjusted one 'on the bench' - probably possible but I would think it easier to have it mounted and the engine running. You might consider that before removing it.
 
Okay, so I've installed a new (Moss) voltage regulator and my ignition light continues to stay on. I now suspect that there is something wrong with the light itself since the battery continues to remain charged. From the schematic that I have, there is only one yellow wire to the light. With the car running I hooked the voltmeter to the source of that yellow wire at the control box and didn't get a reading. Why would the light be on?
The other thing that is confusing me is that the ammeter is in positive territory when the car is running as it should be but when the engine is off and I turn the lights on the ammeter moves further into positive range. It should show the battery being discharged. Can anyone make sense out of this?
 
Ignore the + on the gauge. You have a polarity problem. When you load the battery with the generator not operating it is an immutable fact that you are discharging the battery, regardless of whether the gauge shows a + or a -. The gauge has no prior opinion of + or -. Nor does it know on which side of the gauge the symbols appear. It only knows and shows the physical direction of current flow through it at any given time. The + you are seeing is actually a -. If you swapped the wire on the back of the gauge, it would become a minus. You have a polarity problem. This would include the gauge being wired backward. You might also have a generator, regulator, or battery backward problem (even if you believe it is positive ground and it is hooked up that way). Battery reversal is, however, the last thing to suspect. First question to ask yourself; is your generator working at all. First, polarize the generator. Look for instructions on other threads on this site. (I can't remember if this involves momentary contact from the battery hot terminal with the field or batt terminal!). Then, make a "runaway" generator. This involves removing the batt and field wires from the generator and linking the batt and field terminals on the gen together. Then hook a voltmeter to the jump and ground it as polarized to the body of the gen. Briefly start the car, bring revvs up to 1800, and you should show voltage well above 12 coming out. If not, the gen needs service. Shut it down promptly so as not to generate excess heat in the tiny wires in the gen. You can get more detail on this whole process in the Haynes manual. Been a couple years for me.

Bob
 
Thanks but I've done all that you suggested. I've polarized the generator and then checked it by connecting the two terminals together and to a voltmeter. It checked out. The regulator is new but the light remains on same as with the original regulator. The battery is not discharged. So why is the light on? I understand that the ammeter may be wired backward but it still shows in the positive zone when the motor runs. Why then with the motor off and the lights on is it still further in the positive zone?
 
It's time to open the back of the instrument panel and take a look at the wiring to the light. One side should be yellow, and connect to the control box terminal "D". The other side of the light should be white, and go to the ignition switch "switched" side. If your generator is working and the light is still on, then it is mis-wired.

Next, if you don't like the direction the ammeter registers, then while the panel is out, reverse the wires that go to it.
 
I see now your post on polarizing and runaway. If you have the car running, the ammeter shows +? If you turn on lights when running, does it show more plus or less plus or stay the same? Ignoring the ammeter temporarily, if you have the car running, say about 2000 rpm, and put a voltmeter across the battery, how many volts does it show?
Bob
 
CJD said:
It's time to open the back of the instrument panel and take a look at the wiring to the light. One side should be yellow, and connect to the control box terminal "D". The other side of the light should be white, and go to the ignition switch "switched" side. If your generator is working and the light is still on, then it is mis-wired.

Next, if you don't like the direction the ammeter registers, then while the panel is out, reverse the wires that go to it.
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Yes. that's the next step.
 
Since it sounds like it'll be your first time pulling the instrument panel, you'll speed the job if you keep these in mind:

1). There are 4 brass screws that hold the center panel in place. 2 on the bottom, and 2 inset to center a bit at the top.
2). As the panel pulls out, you will have to disconnect the oil pressure line on the left side. The panel will not pull out very far until this is disconnected.
3). The tempgage has a rather fragile capillary tube attached. As the panel comes back, you have to gently loosen and feed the capillary out. If it is still like stock, the capillary is clamped to the right side of the heater, so removing that clamp will free at least 2 feet of play in the capillary.

After that it's a pice of cake!
 
I started to investigate the wiring behind the instrument panel. I seems that not all wires are color coded correctly. Before I remove the panel I want to make sure I have everything needed to put it back. The biggest problem I see is that the body of the ignition key switch is cracked and the two terminals are loose. Also are there tools offered to remove the chrome bezels at all the knobs and before I break the knobs in an effort to remove them, how do they come off? the panel is held on by regular nuts and would like to replace with wing nuts to make it easier to remove. I'm assuming that they aren't American Standard threads. It looks like I'll have to make it a project to make sure that the wiring is correct and try to make some order out of the "rats nest" that is currently there.
 
The knobs have little buttons underneath. By depressing the little buttons the knobs pull straight off.

There is a bezel tool, but I have never taken the time to buy one. I have made do with the points on needle nosed pliers. But a tool would be nice!?!

At this stage in the car's life many of the wires have faded to either no color or even different colors because of age. An ohm meter and light test probe are very helpful determining where the odd colored wires actually go.

I have had no luck replacing the brass wing nuts. I believe they must be Whitworth threads, but I'm just guessing. I attempted re-tapping to a modern thread, but had no success. I finally pulled them off a parts car.
 
CJD said:
...I have had no luck replacing the brass wing nuts. I believe they must be Whitworth threads, but I'm just guessing. I attempted re-tapping to a modern thread, but had no success...
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Not Whitworth, but British Association (BA) threads. Most of the threads smaller than 1/4" on the TRs are BA threads. The two that I've run across are 2BA and 4BA. They are sort of a mix of inches and metrics...from Wikipedia...

"They are unusual in that they were probably the most "scientific" design of screw, starting with 0BA at 6.0mm diameter and 1.0mm pitch and progressing in a geometric sequence where each larger number was 0.9 times the pitch of the last size. They then spoiled this by rounding to 2 significant figures in metric and then converting to inches and rounding to the thousandth of an inch."

Anyway, below is a link of a thread chart from British Fasteners. They also have BA taps and dies, along with hardware, however, I've just re-threaded standard hardware when needed. All I've found that I need on my TR3 are the 2BA and 4BA sizes.

https://www.britishfasteners.com/threads/index.html
 
martx-5 said:
Just ran across these wing nuts on E-bay. Not brass, but should fit. I'm pretty sure those dash wing nuts are a 2BA size (0.185"x 31.4tpi). Check the studs to see. Notice how close 2BA is to 10-32. Should be able to start to thread a 10-32 on there then it will stop.

https://www.ebay.co.uk/itm/10-x-2BA...913018?hash=item41902f9a3a:g:tcUAAOSwstxU1hVh
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You're absolutely right! The 10-32 was so close I thought I could run a 10-32 tap down it and use a 10-32 wing nut. Turns out they are so close in size that I just wound up with a real mess down the stud...and then neither type nut would tighten.
 
I just found different sized teflon wing nuts at the hardware store. If I find one close to the threads on the studs they may just tap themselves as I screw them on. I think that they are soft enough and won't ruin the threads on the studs.
 
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