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TR2/3/3A Ignition light on TR3....

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K

karls59tr

Obi Wan
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Well the red ignition light stays on while driving. Here's what I've done so far to try and track down the problem. Tightened the fan belt to spec. light stays on. Polarized the generator and regulator. checked the wiring from Gen to Reg. OK.Got 12 volts when testing the Battery. Started the car and at 1400rpm got a reading of 11.93 volts on the Battery..supposed to be 13.5 to 14 I believe.. so I assume the generator or regulator is causing the problem. I took a small file and filed the points in the regulator but I haven't sprayed the internals with electrical contact cleaner as was suggested somewhere.
Moss has a video to test the generator but they want you to have the idle at 850/900 whereas my car with a cam idles at 1400 so unsure if the test would work.It might be time for the generator to get new brushes etc but I'd like to rule out the regulator.
Is there a way to test the regulator to see if that is the problem? I do have a spare regulator somewhere I suppose I could install to see what happens?
Unsure how to proceed from here.....any suggestions?
 
First, you want to test the generator or rule it out as the source of the problem.

I've just seen & solved the same problem this afternoon. In my case this generator has never been on the car before and initially the red light was on.

First thing I tried was re-polarizing the generator. disconnect both leads and then use a piece of wire from the small terminal to the battery - just touch it for a moment a few times and you should see a small spark each time - this tells you the field is drawing some current. Don't leave it connected continuously. You're putting some residual magnetism in the generator, like magnetizing a screwdriver tip.

The red light was still on after this. So I tried the factory manual procedure of connecting the 2 generator terminals together (and disconnected from the harness) and measuring the voltage from there to ground. I started it up and saw 1.5 volts - not much. I revved the engine a little and saw 11-20 volts as the manual says. It also warns you not to exceed 2000 RPM - because you are running open circuit without a battery connected and you don't want to generate huge voltages.

Finally I opened the control box and pushed on the levers to make sure everything was moving freely. Do this with the battery disconnected. Started it up and no red light! The ammeter is on 0, but goes halfway to 30 when I rev it just a bit. 13.5V on the battery.

Keep in mind I'm reviving an electrical system that hasn't been operational for 32 years before today. Yours was running and something has changed. These tests won't hurt if performer properly - give it a try.

If your generator has good output in the second test, connect it back up with a jumper between the 2 terminals and it should be charging the battery. You've bypassed the regulator so don't drive it that way, but it will rule out the generator as a problem.

Andy
 
There is a more methodic set of tests at
https://drive.google.com/file/d/0B2...NDNmLWI0YTYtNjY5ZjQxZTA2NGFm/edit?usp=sharing

But the sequence Andy gave is basically correct. Disconnect the two wires and link them together (preferably through an ammeter) with a voltmeter to ground. Start the engine and watch what the voltage does. If it comes up past 12 volts with the engine at fast idle, then the generator works at least enough to turn off the red light. That leaves either wiring or the control box at fault.

The red light is basically controlled by the cutout relay, which is supposed to close when the generator output reaches a bit over 12 volts.
 
Nope, no oil light on a TR3. The red light is called an "ignition warning light" in the book, but it essentially indicates that the key is on and the generator is not working.
 
One other point, if you do find that the generator is bad, make certain to double check that the regulator is working properly. One of it's functions is to limit the output from the generator, so the generator doesn't overheat. Otherwise it will cheerfully put out enough current to burn itself up! Another way to check is to pull the old generator apart and see what's wrong inside. If it has been overheated, the damage will be obvious. Solder thrown from the commutator is a clear sign.
 
TR3A. 1960:

I want to thank you guys on this thread. My red ignition light just started staying on & the ammeter was stationary, had no movement at all.

i was leaning toward replacing the generator & the regulator, until I found your forum.

upon advice I found here : I checked all the wiring under the dash & hood.
found two wires, in the generator/ignition chain, needing replacement. Then I re-polarized and "bingo", saved me a few hundred dollars & increased my TR3A education considerably.

Thx again.

gtp1960
 
Well done.

It is exceedingly rare that I have a TR problem that has not been identified, discussed and resolved here sometime in the past -- a search here is like having Randall in my garage.
 
I agree with Geo.

There are some wonderful people on this forum and I have been lucky enough to meet some of them. I have also been lucky enough to not break down in order to meet a few more. -but I doubt I will always be that lucky. Just knowing these guys are all around the country makes me never feel alone.
 
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