Hello (posting this a second time in the right subforum)

Have ongoing issues with 1997 XJR and starting issues. First off I have replaced alternator and battery, still unable to keep battery charged. Sent to mechanic and he suspects electrical draw somewhere but cannot find. He gets a good charge on battery and it runs fine. I put a on/off switch at the battery to kill the electrical demon sucking the life out of my battery. Start the car every week and it starts fine, it's not a daily driver. I let 2 weeks go by (bad mistake) and now unable to start. Doesn't even turn over. The voltage at the battery is 12.4V with 675 CCA out of 825. The battery light is on and the voltage gauge in the car shows about 10V. No matter how much charging I do or jump starting it will not turn over. When I have it connected via jumper cables to another car the voltage in the car will show 12V and not start. When I have it connected to a battery charger it will show 10V. I have checked all the pertinent fuses and relays. I am stumped at this point. Any suggestions would be welcomed.

Addendum: just went outside to try another go at it after reading about 25 different posts with similar problems. I noticed the red P indicator light is not on (now that it is dark outside), so this is one issue that needs resolved. Neither does Neutral. Only Reverse and Drive light up. How do I fix this problem?

 

After more searching and reading it looks like adjusting or replacing the gearshift linear switch is the place to start. Pun intended.

 

Solenoid? Even with the reduced amount of juice in your battery, it should manage to produce a click or an attempt at turning or some sign of life. Assuming of course that the electrics remain otherwise ok, which they seem to have been, before you fitted the on/off switch........ A random and unhelpful thought could be that your on/off battery switch has fried something. The electrics are sensitive to power surges, and I wonder if the switch perhaps doesnt always make a "clean" contact.