I have been troubleshooting my 1986 240's charging system and have a question that I have not been able to answer from the manual or FAQs.....

The alternator dash light works (come on with the key), and I have full battery voltage(~12.6 V) at the small red wire that plugs into the D+ alternator connection when this light is lit. BUT...when I plug the small red wire onto the D+ spade voltage drops to around 1.65V. I checked resistance between the D+ spade and chassis ground and find about 650 ohms.

Is this normal resitance normal between D+ and GND?

Is this resitance acting as a "load" and pulling down the 12.6V to 1.6V?

Is this normal?

I am getting 13.4 - 13.7 volts at the battery while car is running at idle with all loads turned on (I believe the battery is now >90% charged). Voltage is not much different with loads (lights, flashers, rear window heater, etc.) turned OFF. When I rev the engine the voltage actually seems to drop a small amount...I thought that this would increase.

All help is appreciated. Will a Great Thanksgiving if I can give son his car back today!

Thanks to all in advance,

Cliff