Last week I replaced the D+ and checked for problems in the B+ wire.

You replaced the D+ wire?
How did you check the B+ wire? Starter treminal too?

You get several warning lights when you turn the Key On, but do they include these 4?

• Batt
• Parking Brake
• Brake Failure
• Bulb Failure

If not, your (good) alternator will not get the required current at D+ to start charging as it spins up.

If you do get all 4 of those lights, a good alternator should put out at least 13.5 to 14.0 volts at idle.

Measure at the B+ terminal post and at the Battery + post. If the Battery post is not within 0.5V of B+, remove the battery Negative cable and clean all B+ wire connections—including at the starter and the inside of the Battery Positive terminal connector.
Do the Battery Negative connection too when you reconnect it.

You don't give us the car model or year, but if an '80s 240, you may also have cable problems where they run under/behind the crank pulley.


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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.