I know that someone kindly bunched all of the car won't start threads together, and I thank them for that. However, it will take many hours to wade through them all, so while I do, I thought I'd post my problem, to see if anyone just happens to know the answer. I have also posted the same thing on other sites, hoping for a response. (Is that the definition of insanity?)I have read and re-read a ton of threads on here and elsewhere, and don’t know where to start. I am not very mechanically minded, though I’d like to be.

Here is my issue, with a preamble about the car. Any help/advice is greatly appreciated. Please remember you are talking to someone that needs layman’s terms and probably diagrams if it gets complex! Thanks again.

I have had my Jag XJ6 since 2005. My wife bought it for me, reasonably priced, as I always loved the 80’s XJ’s in the 80’s when I lived in bonny Scotland. Since ownership it has had various issues, resolved by a mechanic that knew Jag’s. That mechanic is now retired and money is also tight.

Car has been garage bound for 3yrs and not run in that time. Both her in Florida, where we now reside and previously in South Carolina.

I have not had to use the car and I suppose I just got used to not having to move cars around to get it out. I know I should have and, believe me, I regret it now.

So, now wanting to get it back on the road, I have hit this problem.

I bought a brand new Duracell Size 49 H8 Battery. 12V 900 CCA. After installation, I held my breath and tried to start the car. Needless to say, I am here as it did not start.

Here is what I noticed:

It did not click, as when trying to start when battery not charged.

The doors do not lock electronically, at all.

All other electrics, seem fine, lights etc.

I had thought that the lack of beeping and the not locking of doors electronically might be related to the security system. But, I have no idea how to narrow that down.

A few years ago, I bought an after-market stereo and, somehow, managed to install it. During the time of it not being used, I uninstalled it and put the old one back in. Old stereo no longer powers on.

Tomorrow I am going to remove the stereo and check the connections on the cradle, then look for fuses related to the stereo. I have no idea if it is related, but it gives me something to try!

I also tried knocking on the starter, assuming I got the right part, with a metal rod as I have heard and seen people claiming that can work.

Forgot to mention, and I’m sure it’s pertinent, voltage shows on dash at just over 11v. As stated above the battery is 12v. Where are the missing volts?

Again, any help greatly appreciated.

 

First thing I would do…I would bring the battery to the starter terminals and see if the car will start with power applied directly to the starter.

I have an XJS, and not an X300, but the missing voltage could be enough to prevent the XJS from starting.

To make things easier in the beginning, if you had a trickle charger, I’d tie that to the battery overnight and see if anything changes before following my initial suggestion.

 

Vee,

Thank you. I will see if I can access the starter terminals, but that seems a bit tricky as it would mean mounting it next to me at the engine. Do you mean using jumper cables?

The battery is brand new. Do they ever come new and not fully charged? I will see if I can check though. Have to wait until I pick up meter from in-laws next weekend.

Appreciate the reply.

 

Yes, I have bought new batteries that were not fully charged.

 

Seems to be a website calender error as old thread

Fresh Meat ,

Did you remove the fuse for the alarm ? SLCM during storage to silence the alarm ? fuse # 3 or # 4 in trunk

Installed battery in backwards ? positive post goes car fwd , never over tighten positive post bolt as splits the special curved nut underneith

Will be adding to this post even though you may not replie tonight as late

For a non - running / amperage draw anything 11 volts is a huge drop unless the starter solenoid is engaging ...........and on from there

Place finger on the starter solenoid relay and feel for click ( this splits the starter system trouble shooting in half )

You will have to use finger as other relays in area click , but you have total silence

Pics coming




For the 4.0 liter setup

 

Parker 7,

Thank you very much, for your detailed reply. I am not very good at this, so pics helped a lot.

I will try this when I get home from work later today.

For the clicking on the solenoid relay, you mean have someone try to crank the car and feel for it?

Positive towards front of car, as you say. The battery connectors are not what came with the jag. There are parts missing and I just had to attach and put a hose clamp over the two ends of the negative. I'll send a pic. Do you think I can order replacements to fix it back to what it should be?

Thanks again!

 

Yes the click feel is 2 person as other relays will click giving off sound

The battery connections substitution is something I looked into but didn't come up with anything , I'm sure others have

You can have an open cell on the new battery and can be tested by running the cabin blowers and watch your gauge as a 1/ 4 to 1/2 volt drop would be normal

I'm off to get a surgery today

 

Reading this on lunch break. Will try running the blowers later too.

 

Internet bad so will edit this post line at a time

Quick and easy test , have key in run but engine not started

Remove each small relay in the corner of each 5 fuse boxes , with the exception of the left engine bay fuse box

The left only runs the car horns so a swapping option

The right engine bay fuse box relay first try as powers fuse # X which is the first power to the Engine ECU as this provides a enable to the starter system

The relays should click in your fingers back to open

First try right engine bay fuse box relay as this powers fuse # X as your engine ECU poer as this provides a enable for starter system

This ensures power gets to all points of car to do their thing

For the starter solenoid relay check the key has to be rotated to start position with all of the fuse box small relay installed

With a meter you can check the the starter relay has a command to close as a ground provided by the enable summation device being the body processor module
on socket 1 as 2 is power from a fuse that will blow meter if on resistance knob selection , this makes it a signle person operation , the engine valve cover is not a good ground for your meter leads

 

I ran through the fuses in the luggage compartment when I got home tonight, but that's about all the time I had.

I found one 15amp fuse broken, but in looking at the fuse diagrams, I think this may have only been for seat heater. Could be wrong though. Either way I will pick up a new fuse tomorrow and replace that one.

I found the diagram that shows the locations of the fuse boxes and will follow your instructions on removing the relays next. When you say that the relays should click, do you mean when I remove then put them back in?

Also, I do have a meter but have never used it before. I will look up how to do that. As I said in the initial post, I am not very mechanically minded but will give it a shot. I'll try the relays tomorrow evening but will have more free time on my day off, which is Thursday.

Thanks again for your help.

 

re hose clamp on negative terminal. Make sure that the connection is tight. You should not be able to rotate the post clamp if it is properly installed. Not sure how often you plan on driving the car, but inactivity will drain the battery and shorten its life. A battery tender is your friend in this case. This is what I use:

 

The battery tender will always keep your battery fully charged, and will not "cook" the battery the way that an unattended charger will.

 

the single small relay on the fuse boxes will click on the way out of socket and click back closed ( powering fuse 10 , 12 , 14 , and 16 for the 4 fuse boxes ) on the way back in

Just remember to not test for voltage or a power wire on the resistance knob setting ( blows a fuse inside meter )

Fluke meters has good tutorial videos but pricy meters

See page 21 as the # 1 fuse is closest to the power terminal stud

X300 1996 LWB.pdf

 

Did you say your keyless isn't working? That sounds like body control module, went through this on my XJR. It's been a minute since ive been around that problem but i remember keyless not working and some other issues with door locks and things. It's a well-known X300 issue.

 

For your lock/security issues, would a dead battery in the key-fob do that? Cheap and easy enough to try.

 

Key fob was not working when I bought it in 2005. I just used the key.

I took out the relay switches and replaced, no clicking anywhere, that I could see/feel.

Checked all fuses.

Used a meter to test voltage of battery. Around 12.5v. Dash still shows 11.

Should I try jumping it. If that works, then likely the starter?

Thanks to all replies.

 

The relays in the corner of the fuse boxes are commanded by a ground path through the ignition switch to pin 5 ( black wire ) to car frame ground

If the IG switch needs replacing it removes from key barrel so no new key needed , for testing you do not need to remove IG switch ( red object )

The later more around X308 V - 8 powered same chassis is exatly the same part for the X300

The black ground wire ground stud can get disturbed by things like stereo upgrade

Fluids like coffee can spill into IG switch connector as my pin 5 was green with corrosion

Pic coming

Ask questions

On your FOB / SLCM / security system the same IG switch from pin 4 to 5 on key removal makes the SLCM go through a lock up sequence that it may be back " on " the time you were last during driving it , the SLCM provides a enable for starter rotation

You owe me a beer

 

There are 2 tricky set screws on IG switch remove that has to be the right blade thickness as the slot is cut wide and a smaller blade will spin in slot , put towel down as the tiny set screws can get lost

 

Are you saying that I need to remove the ignition switch? i.e. Where the key goes into (Sorry laymen need laymen terms lol) If so, how do I do that? You mention the screws being tricky to remove. I don't even know which ones those are.

Does that connector come off without removing the switch itself?

Also, any thoughts on it being starter or alternator? How can I rule them out? Again, in laymen terms, if you can. Should I try jumping it? Would that take it from the 11v on dash up above 12v to crank?

I feel like I am in over my head. These cars are crazy complicated.

Of course I owe you a beer. If I get there I'll get you a case. If I could ship it to you, I would!

As far as the SLCM goes (security locking control module?) Where is it? If I never used the keyfob, how does that come into play. As I mentioned before, it used to lock with the key. As in all locks would engage, chirp and alarm would set. It no longer does that.

 

The IG switch does not need to be removed to test that and the ground

Editing

The IG switch is the heart of your electronics system controlling your king relays on the fuses box along with your security system

The IG switch connector ( 5 wire ) is by removing the small curved panel just below the steering collum and the car side of the connector lifts straight up from the dash mount to bring work out to you