WAIT! Your battery may not be charging because your BATTERY sucks. Before buying ANYTHING, have it checked. A bad battery can show everything AND cause your fans to run.

 

 

How old is the battery, date of manufacture? Do you use any sort of battery tender or maintainer?

 

 

When you say "i checked the voltage with the car on and it showed 13.29", is that with the engine running or just the ignition on and engine NOT running? If you are getting 13.29 V with the engine running I will be surprised if the alternator is really not working.

 

Others may want to chime in here but I was under the impression that the earlier charging systems would put out 14.2 volts at idle . If the OP would keep a volt meter on the battery while it is idling my bet is the 13.29 v will start to drop . If so the voltage regulator is most likely toast. The 2010-2015 charging system normally runs at 13.5 v +/- and will spike up to 14.4 +/- during deceleration . This has been my experience.

 

Pull the right side front fender liner out and unplug the fans, then see if it'll show a charge when you rev it up. What check engine light codes are you getting? When I bought mine the fans ran all the time because the wiring had chaffed against the road and the control wire was cut. The engine processor talks to the fan controller (in the fan hub) and tells it how fast to run. If they don't talk, the fan runs wide open and it will kill the battery quickly. I also assume that if you alternator is bad, the fans extra load is what killed it. Fix the fan, make it charge, make it hold a charge, in that order.

Fans are common with S types and I assume XJ's so they aren't overly expensive.

 

 

With the ignition in the OFF position for at least ten minutes, there should be a minimum of 12.6 volts across the battery terminals. If not, the battery must be replaced regardless of what the parts house people say.

 

If it's like mine was, with the fan running full tilt all the time there's barely enough output from the alternator at idle and no output when the engine is off to keep the battery topped off and it'll kill it over time.

A better check would be to charge it, leave it unhooked from the chassis over night and see what it reads in the morning.

 

 

Replace the battery.

 

With the engine running you get 13.29V. This means the alternator is doing its job and is not the problem. I would not replace it. As already stated the battery would be my first suspect. Its a LOT easier to change than an alternator.

 

Fix the damn fan... The rest will sort itself out.

 

 

 

Get all of the codes read first. Then determine what they relate to and post up the info.

 

 

All of this points to a low voltage output from the battery. BATTERY!