Hello All,
89 v-12 ,
The original owner was having issues with the battery holding a charge.
I started her up and removed the battery cables and she continued to run just fine. So I know it's not the alternator.
We did notice that the passager side door light remained on while we were checking out switches. So I'm thinking parasitic draw perhaps. I'll disconnect this over the weekend if I can't find out out how to turn it off.
Peace
Neil

 

Hi Thuffner3
Ahhh...chasing electrical gremlins...what joy! A stuck light certainly will kill the battery. How quickly does it drain?
I didn't even bother testing the Lucas alternator when I pulled the engine on my XJS, I switched it over to a GM alternator.

 

what does the guage read when the cars running?

hows the fluid level in the battery?

the light should turn off when the door closes and hits the switch in the door jam. Check it.

 

Check the voltage at the battery terminals when engine is running. It should be slight more than 14V. Less than 13V means the alternator is getting weak.