Triumph Repair: 79 Spitfire ignition light, brown wires, test light

Question
First.....thanks so much for the free assistance......more valuable than you experts might realize.  My ignition light is on with the ignition switch off and the key removed.  If goes off when I turn the ignition switch on without starting the engine.  Thanks again....Rory

Answer
Hi Rory,

First test is to remove the wires from the back of the alternator and see if the "Ign" light goes out. If it does you need to repair or replace the alternator and/or regulator.

The "Ignition" light is not an Ignition light, it is a "Alternator Charge" light. Don't ask! it is a British thing. ????? Something like Bill Gates telling you to hit the "Start Button" to turn it off. ???

It can be a wiring issue too so run this test. Connect a volt meter across the battery and read battery voltage. (12v +) Now start the engine and set it at about 1500 RPM and read the voltage. It should read (13.8v to 14.5v)

Another test of the alternator is to remove all of the wires from the back of the alternator and put a 12v test light between the brown wires only and the post on the back of the alternator. The test light should NOT light up. If it does light up you have a bad alternator or regulator.

If you do get those readings it can still be a bleeding diode in the alternator or the wiring from the ignition switch to the alternator needs to be traced. If you don't have a diagram let me know and I will post one on my web site for you to copy. Let me know.

Howard