recently my XJR is developing some electronic issue.

turning the key , not responsive or getting some dimming light on the dash cranking up.


but the battery and the alternator are both less then 1 year one. I checked my battery and voltage seems fine. cleaned up the battery terminations as clean.

every time. I have to reconnect my battery to start up my car.

same thing happens when car is idling at red light, dashing board is dimming and ABS light it turning on.

it will go away once car moves again

 

You either have a bad alternator or bad battery. ABS is almost always the first for acting up when voltage gets low. I think i remember anything below 11.5 volts. At any rate either the battery is not charging or the alternator is not putting out. That is the worst case scenario. More than likely you have a bad battery cable, bad grounding cable or bad ground connection. The cables may look good but the corrosion is inside the crimp connector.
Attached is a great troubleshooting guide one of the forum members developed and i really am going to have to look up his name. Follow the directions for troubleshooting and you will most likely find the problem.