• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR2/3/3A Red ignition light stays on...TR3?

Share this page

K

karls59tr

Obi Wan
Bronze
Country flag
Offline
I'm pretty sure this has been dealt with before but what is the best procedure to track down this problem? Car starts and runs fine but know there is an electrical glitch somewhere.
 
If it was working before, I'd probably start by disconnecting the field wire from the control box, and checking the resistance between the F and D terminals on the box (engine not running). You should find nearly zero ohms; if not then the regulator contacts are probably dirty and should be cleaned & adjusted.

Next simple test is to disconnect both field and armature (F and D) wires from the control box, and temporarily connect them together with a voltmeter to ground. Start the engine and watch the voltmeter as you rev the engine up just a bit. If you don't get 20 volts by 2000 engine rpm, the generator (or the wires to it) are bad & must be serviced.

Beyond that, I'd follow the procedures given in https://docs.google.com/viewer?a=v&p...Fm&hl=en_US
 
Same issue with my 1968 GT6.

I started checking the generator first and discovered some problems with it. Will get that part sorted first before going to the control box.

Here's some sites I used for assistance:
<a href="https://www.rootesparts.com/id211.htm
" rel="nofollow" target="_blank">Electrical Tests</a>

Lucas Generator and Control Box Tests

Working on getting my generator rebuilt prior to seeing if there are other issues.

jb
 
One other thing, on the generator tests I was only outputting 0.3 volts and that is why I concentrated more on the generator.

Will see if there are other problems later.

jb
 
One thing to keep in mind, a bad control box (or a short in the wires) can ruin a good generator fairly quickly. At higher rpm, the generator will easily put out enough current to overheat and fry itself; only the control box keeps that from happening. If you see over 20 amps charge on the ammeter for more than just a few seconds, you should probably shut the engine off and look for the problem.
 
Well I discovered the problem. The fan belt was loose because the upper adjustment bracket bolt had worked itself out and fallen hence the glowing red light. As a temporary fix I installed a 1/4" bolt 1&1/2 " long using 5 washers on the bolt head and a lock washer and Loctite on the nut end. Anyone know what type of bolt the original is? Looks like coarse thread? wonder if it would have had a nut on it as there is not much room for one near the block. Maybe it was just screwed in? Years ago I had dealt with the other generator bolt issues so hope this is the last one.
 
Are you talking about the bolt that holds the bracket to the pump housing? Or the one that clamps the generator ear to the bracket?

Both are supposed to be 5/16" NC, 1.25" long; but the bolt into the WP housing is supposed to have a lock tab on it, while the generator bolt is supposed to have a jam nut on the other side of the generator ear. There is also supposed to be a plain washer between the generator ear and the link.
 
Back
Top