Came out to start the car and battery was a no go. The battery is 4 weeks old. I have notice that the drivers seat easy exit is not working. What is the best way to determine if the alternator is working. It may be that the seat module is shorted and killing the battery??
Put in a new battery and started right up but don't want to kill this one until I can do some testing. Any recommendations on where to start.
I jump started the battery and took it for a long ride. When I got home and shut down it restarted no problem. Next morning not enough juice to turn the starter.
I jumped it a gain and went for a long ride. Got home let it sit for a few minutes and it started right away. Disconnected the positive terminal and next morning battery dead.

 

Hmm, odd one, have you had the battery load tested, remote possibility it's a dud...

Earth points to check out are the engine one, underneath the car parallel with the transmission bell housing, the next one is the earth or negative cable onto the battery, is it in good order and connections tight?

Also check the false bulkhead connections under the hood, one either side, they're large gauge black leads one runs to the fuse boxes at the front, the other terminates at a brass bolt on the front of the brake servo housing.

A faulty alternator should give a no battery charging warning, to test it's output of 14.5V ish running is a case of getting a multi-meter on the battery terminals to see charge voltage.

Have you got any functions on the drivers seat? or is it just the easy out that's not working? Has this coincided with the drain?

 

I have given a hardy tug to the ground strap near the front wheel, made sure the boot ground strap is tight. I looked at and check tightness on the bulkhead connector, visually looks clean, nuts are tight.
I did not get any dash light readings for the alternator. The only odd things of late are the headlight-on indicator in the dash quit working. I got a rear bulb failure and checked all lights they were working and then the bulb failure went away.
The driver seat works with the manual controls, memory doesn't work right now but I have had the battery disconnected. The seat normally retracts to the rear when the ignition key is removed. That feature is not working now.
Interestingly when I jump started the car the first time for the first ten minutes or so I kept hearing an intermittent chirping coming from the driver side rear door.

 

I forgot to answer your question. The problems starting occuring at the same time between the battery and the seat. I noticed the seat not working and within a couple of days I had gone out started the car and drove about 3 blocks to the store. I came out and only got a click from the starter. I pulled and cleaned the battery terminals and hit the key and it started. I drove it home and got up to a dead battery the next morning.

 

Tugging on the ground strap isn't good enough unfortunately. You need a voltmeter to check for a voltage drop between the engine block and the frame. Also for a drop from the false bulkhead to the battery. It can also be used to check for a drain when the car is shutoff.

One possible way to troubleshoot this without a meter is to pull the fuse for the seat power then see if the battery dies overnight.

SeanB, great advice in your first reply, it should be sticky for all the XJ8 electric posts that we see.

 

All good stuff.

On a LHD car the wire to the brake servo housing might not exist or it goes to an equivalent point accounting for the brake servo being on the other side. Or, haven't seen it anyways.

 

@avern1

Tugging at connections isn't going to cut it. You have to undo them, clean them and reassemble. And, unless you know how to do it, a voltage drop test means nothing because the circuit has to be under load to observe the real drop. An unloaded circuit may not show any voltage drop but have a significant voltage drop when used at designed capacity.

 

I will get started in the AM cleaning and testing and get back to you tomorrow.

 

There are two areas that have not yet been mentioned although they are generally not the culprits. Sean has mentioned those already.

Follow your postive battery cable along to a black box in the trunk at the front of the spare tire well. It contains a couple of *heavy* fuse links and some connections. From there the positive works its way up to the front by segments and from the RH rear fusebox and the LH rear fusebox. So, if all else fails you may want to inspect those as well. They are normally not a problem though because they are dry and well protected.

 

Morning test results. Hooked up battery and started the car. The reading across the battery was 12.9 volts. Went for a drive and made to stops checking voltage across the battery each time. At the last stop voltage across the battery 11.6.
Headed straight to the house. Across the battery terminals now 11.5.
I took a reading at the bulkhead connector front connection grounded to engine was 12.9 grounded to the body 12.8. The same readings were founf on testing the backside terminal. It would appear that I am only getting 12.9 from the alternator.
I will check the fusible links and report back.

 

12.9 at the alternator is ok especially at idle. Sounds like your loss is at the back. Check from the battery positive terminal to the chassis. Then check voltages back along the positive cable. It goes through some big connectors and fuses in the bottom of the trunk.

 

I removed the fuses for seat movement. Started the car and across the battery terminals 11.8 volts. Checked the bulkhead connector and read same 11.8. No alternator excitation? I was reading 12.1 before starting and 11.8 idling after starting.

 

Thanks to everyone for the advice and testing info. After all of the testing I decided new alternator time. During the alternator removal I discovered the main cable to the alternator had come loose and had done some serious arcing and damaged the mounting stud. Pulled the alternator off cleaned repaired threads and reinstalled everything. 14.5 volts output and good to go. Discovered the possible reason for not getting a dash indication of NO CHARGE. When I tested it with the negative cable disconnected and the engine running I got 10.9 volts at the bulkhead stud.