Hello, I have 1 65 Lesabre and while the engine is running, the Gen light is on. I have the 1965 Buick shop manual. It states that... --- Indicator Light on - engine On B. Check voltage at field relay coil by connecting a voltmeter from regulator "2" terminal to ground. If voltmeter reading is above 5 volts and the indicator light fails to go out, field relay is defective. ---- When I do this I get over 5 volts (7-8 volts) but the indicator light is still on. According to the chasis manual that is due to a defective field relay... Is there another way I can check to see if the field relay is indeed bad? Will I have to purchase an entire voltage regulator or can I purchase only the field relay? Brook
Check voltage at the battery, it must be + 13Volts if engine is running. If it's below, replace the voltage regulator for a new one. That's my opinion and knowledge.
First, I would check all your alternator and voltage regulator connections. I've had the GEN light on while running and also while it's off with the key out, several times. In every case except one, it was a loose connection
Just in case ... see if the alternator belt is tight or loose .... My Gen light allready lighted and I tighten the belt a little more ... and as soon Gen light goes off ! ou:
I bought and installed a Wells external voltage regulator, and the gen light is still on while the motor is running. The voltage at the battery while the engine is running is 14v. The alternator belt seems pretty tight. -Brook
Is that GEN light like the later ones which can go on full bright or half bright? It can tell you which side of the system the trouble is on
Yes the gen light is the type that brightness can change... When I turn the igintion to ACC the light is very dim. When I crank the car the light gets brighter.
Is it full or half bright while running? This is from the '70 manual but I wonder if it applies here: 20-19 Description of instrument panel-Skylark [GS should be 100% identical] b. Genrator light indicator The red "GEN" warning light should light when the ignition is turned "ON" and before the engine is started; if not lighted [Buick's poor English here ] either the bulb is burned out or the indicator light wiring has an open circuit. After the engine is started, the "GEN" light should be out at all times; if the light comes on, the generator belt may be loose or missing the generator or regulator may be defective, or the charging circuit may be defective. With the ignition switch turned on (engine not running) current flow is through the ignition switch, through the generator light in the instrument cluster, in the "4" terminal of the regulator, through the lower contacts of the regulator (held closed by the spring) out the "F" terminal, in the "F" terminal of the generator, through the brush and slip ring, through the field, through another brush and slip ring to ground Before the engine is started, the generator light should glow about 1/2 brightness. This is because the voltage in the circuit before the light is about 12 volts, but the volatge at the "4" terminal after the light is about 5 volts. This makes the effective voltage across the generator light approximately 7 volts for about 1/2 brightness After the engine is started, the voltage put out by the generator immediately closes the field relay. This causes battery voltage from the "3" terminal to be present at the "4" terminal. Since battery voltage is present on both sides of the light, the light goes out. if the generator light comes on while the engine is running, the charging circuit should be tested at the first opportunity to determine the cause of trouble. See paragraph 68-9
