Hi all, I have a 1997 3.2. The central lock has started to do a strange thing and that is when I unlock the car using the key or key fob the car will unlock and then lock itself three time before finally unlocking for good. The car lock just fine with the key in the door or by using the fob it just has this multiple unlocking and lock when I unlock the car. Any ideas?
the car was not doing this two weeks ago which was the last time I used the car.
any advice?

 

Fully charged battery ? 12.75 volts before starting as a still car

Never install battery in backwards , positive post car fwd , mark positive post with tape and an arrow by marker

Never over tighten the battery positive post bolt , breaks curved nut underneath

 

Wonky power locks usually point to a failing battery...in the XJS. How old is your battery?

After that, I would remove door cards and unplug each power lock actuator to see if there's one that needs some lube, or maybe something else?

 

[QUOTE=Parker 7;2782495]Fully charged battery ? 12.75 volts before starting as a still car

Never install battery in backwards , positive post car fwd , mark positive post with tape and an arrow by marker

Never over tighten the battery positive post bolt , breaks curved nut underneath

Hi there, my battery sits at 14v when running but when engine is ff sits at 11.5 on the gauge

 

Even with the engine running the central locking still unlocks itself then locks itself three times

 

With the engine running and the alternator putting out and 14 v is OK

With the alternator not turning and a fully charged battery and seeing 11.5 can be loose terminals ( as there are about 4 heavy cable terminals ) on the way up fwd to the instrument cluster voltage test point assuming you have a fully charged battery

Test hand meter on the battery post ?

First time investment is ensure battery is good

The security lock control module is a trunk fuse # 3 or # 4 that is hot at all times so we look at the connections between the battery and that fuse

There is also a large connector above the fuel tank that shouldn't be removed yet as can be a pain to reinstall , but it should have a tie wrap on the connector lock bar to keep it connected well


This is a pic of the V - 12 which has the same power distibution , but the BPM controlling the starter is slightly different ( different enables / agreements )

So with a still car and the power coming from the rear direction from the battery you only have the mega fuses right at the battery positive post , the battery cable that goes aft to the trunk fuse box terminal post

With the alternator turning it still has to come back through this battery cable at the battery mega fuse fwd terminal post and the fuse box

On all fuse boxes the fuse # 1 - 9 are hot at all times

The fuse # 10 , 12 , 14 , and 16 require the relay in the corner of the fuse box to close

Which leaves the remaining fuses to be hot at all times



Pic coming

 

Hi all, just an update. The issue with the central locking just ended up being a flat battery. When I charged it full up everything worked just fine. The problem is that after just a few days of fully charging the battery the fault came back and guess what the battery was once again down to just 12.1v. Now if I fully charge the battery and just leave the car on the driveway the battery doesn’t drain at all, if I drive the car I can only do around 200 miles before the battery is back down to 12.1V. So it looks like the battery is not charging while I am driving. My question is what should the alternator’s voltage be when checking it at the battery?

the central locking starts to play up at around 12.24 Volts, at 12.1 Volts the central locking will alway cycle three times, at 12.0 volts the centre locking will cycle continuously until you with lock the car or start the engine.
These x300’s seem to be very sensitive to battery voltage

 

A turning alternator should put out 13.5 to 14.5 at the alternator large B + post

Ever get a alternator light on the dash ?

There are a few battery cable terminal post to check in the charging path back to the battery

Take a look down through the intake manifold on the starter solenoid and check the first tie of 2 cables connection










Pics coming

Remove the battery cable on the right wheel well terminal post on the engine compartment side , wiggle bare post , this would indicate a loose cable inside the right quarter panel

Back at the battery there is the mega fuses right at the battery positive post , do not overtighten the bolt on the positive post clamp , breaks the saddle nut underneath

There is one last connection terminal as you remove the rear seat pan but is some work so last thing

 

Thanks for that. Well I got my hands on a voltmeter and with the engine of the battery was at 12.45v ( the gauge on the dash was reading 11v. When I started the engine the gauge on the dash went to 14v and the voltmeter on the battery was readying 14.4V. Is this correct/right?

 

Yes somewhat , there is a relationship of current flow restrictions and reduction of voltage ( current and voltage trade each other in restrictions ) if say the cabin blowers are running in a driving environment

With the engine off the instrument gauge is reading from the battery fwd through battery cable terminal connections , 11v

With the engine running you are reading the higher of both alternator and battery so will be alternator and the gauge's test / pickup point , 14 v

Not clear to me if the instrument gauge test point is the alternator round 2 wire connector ( red alternator light signal from the voltage regulator to the instrument cluster , the 2nd wire on the round alternator connector comes from right engine bay fuse box fuse # 12 ( ? ) ) or the voltage supplied to the whole instrument cluster and where exactly it is picking up from

So that's clear as mud , someone can do a better way of interpretation or explaination

Inspect battery cables terminal points connections through car?

Could be the battery itself is current limited / bad but then the car starts

 

Along with the possibility of low voltage appearing at the lock mechanisms, you will certainly have a mechanical resistance in the door lock mechanisms. The main lever on the latch that unlocks the door is hard to move due to years of dirt build-up. This then makes it harder for the mechanism to open if the power into it is reduced. In your case the third try of the system to unlock the locks is enough to free up any sticky lever, at least temporarily.

If you have a mechanical door lock button on top of the door that is springy, that doesn't want to stay in the up (or down) position when you pull it manually, you found the trouble spot. Of course to correct it you have to access the latch inside the door, to clean and lube it. Once that is done, the battery will have no problem unlocking at one try.

 

" If you have a mechanical door lock button on top of the door that is springy, that doesn't want to stay in the up (or down) position when you pull it manually, you found the trouble spot "

Spot on for mechanical loosening up of the identified / which door mechanism

There are a couple of threads on the lock mechanism get to and refurbish as is common

There are some external peanut relays ( in the left heelboard area ) from the SLCM that can be current compromised to drive door locks and swapped but unfortunately , they seem to have different part #s when I last looked ( different color bands )

See page 27 and 148 for your 1997 model year right hand drive

jagrepair.com/images/AutoRepairPhotos/jagxj1997.pdf

Now how these components are powered on different point on the car.................

Even with the engine running the central locking still unlocks itself then locks itself three times

You have good voltage coming from fwd alternator ( but there is a correlation , clue with locks still cycling pointing to either power through connections to , or door lock lube )

with the engine of ( off ) the battery was at 12.45v ( the gauge on the dash was reading 11v.

Not so good coming from aft from the battery

The SLCM is powered from the battery cable going aft from the battery and it's terminal post on the mega fuse carrier ( at the positive post ) and the terminal post on the trunk fuse box , fuse 1 - 9 are hot at all times

The door lock relays are powered from the left heelboard fuse box fuse #s...................

You can follow the power heavy battery cables and their route to the fuse boxes in the pic on post # 6

the alternator battery cable comes all the way aft to the terminal post under the rear seat pan ( not to be confused with heelboard / ankle area ) and then comes back fwd for the other fuse boxes

Fuse # 10 , 12 , 14 , and 16 must have the king relay in the corner of the fuse box close fully ( swap with the left engine bay fuse box relay )

One of these # 10 , 12 , 14 , or 16 is your fuel pump relay control power , I think you had starting issues