Hello to all. I am working on a 2004 S Type Jaguar. Original complaint was that the cars battery dies while driving. I proceeded to have the alternator rebuilt. Now upon installation of the alternator, the battery indicator is on along with the check engine light. I checked the voltage at the battery while the engine was running. I see 13.8-12.89 volts. Also, I noticed while checking fuses and such, that the voltage of the battery was dropping while the VOM was attached. It probably went to about 12.0-11.7 volts. The car did restart and the voltage output at battery went to 12.8-13.5 volts. Any suggestions? Also, my partner stated that the year of the vehicle was a 94 to the alternator rebuilder. could this also create this scenario?

Thank you in advance!
Blessings
Charles Butler Jr.

 

if your not seeing a MINIMUM of 13.8 steady voltage (usually 14.2-14.4) than the alternator is not doing its job correctly. Even with the headlights and a/c running, 13.8 should be easily attained. In the automotive electrical world,with the vehicle running, 13.8 is the magic number. 12.6 is also the magic number for the battery itself.

also, the voltage requirements for the 2004 are WAY DIFFERENT than the requirements for a 1994

 

We also had the alternator checked and reinstalled it. The battery indicator went out for about 3-5 secs and comes back on. If the car sits for a period of time, the indicator will go out right after the start up, then right back on.
secondly, I noticed that the headlights do not work. The high beams do. The dash headlamp indicator comes on though. Mentioned that to see if anyone has had similar problems.

Thank you in advance

Blessings

 

Voltage is 13.6-13.8. Steady. Drops to about 12.8 with everything on.

 

12.8 with all accesories running is too low, i know you may not want to believe that, but it is too low. 12.8 is insufficient charging output with accesories running. like i said before you must see 13.8 with all accesories running or you are doing nothing but loading the battery down. 12.6 battery float charge, with a minimum of 1.2 voltage for charging, is 13.8. if your not seeing upwards of 14.2-14.4 while running with no accesories added into it, there is a problem with the alternator, whether it is rebuilt or not.

 

and im in torrance, which im literally right down the street from you anyway. Feel free to come look at my voltage in my s-type if you dont believe me. i run at 14.2 with a/c and headlights on.

 

So, short version: swapped alternator and then have a new fault. Almost 100%: something wrong with the swap (the actual device or the way it's been connected or something).

 

Charles,
Did you get the car running? I have a question for you regarding the swap; I would have sent you a private message but I don't see that option on this forum.

Thanks,
Ian

 

As a new member your account will be a little limited.. That said, since it is a related topic I would ask your question here.. The OP (original poster) looks like he may have came and went since his total post count equals the posts on this thread.. So.. Ask away, lots of helpful people here... Don't forget to include details about your car like year and engine...