Ahoy,
First post, but here goes:

I have an 87 V12 Sovereign that developed an intermittent fault with all the instruments and trip computer going dead. At the same time starting became problematic as it would appear that the ignition circuit had no power intermittently as well. (No power to starter, then a few minutes later starting with no problems...)

Today I decided to have a fiddle and see what I could find. I saw a post on here regarding the fuse for the trip computer, but that seems to be ok and there is power to the fuse board. I ran a wire from an "ignition on" source to the fuel gauge and it spooled up, so that confirms that there is no power.

I haven't managed to find the fault yet, but while rummaging around I seem to have bumped something in the ignition circuit to make that worse too. All I get now is clicking so am stuck until I can get it sorted. Anyone have any advice?

Thanks

Bruce

 

Edit: The clicking is because I ran the battery down while working on the car........

It's on the charger now.

Thanks

Bruce

 

Oh, oh. Unless you did a lt of cranking or had a lessor load on for hours, the battery is suspect. Older sand sulphated batteries have limited capacity.

Was just there while wrestling with a no brake light issue. Messed up my diagnostics in circuit tracing as well.

New battery after the old refused to take a full charge and my circuit tracing worked out. Fixed and lights are now fine. Smart charger told the tale.

Another mess in process, but that is for another day, maybe. Goofed there good!!
Son helped me outta that one. Metal moving genius.

Load test your battery. Your gremlins may go away if it tests poorly and you replace it.

Carl

 

The battery drained down over a couple of days of fiddling. It didn't help that the kids left the rear reading light on over the weekend........

Battery is fully charged this morning and it starts with no hesitation.

I'm pretty sure it's a loose connection somewhere. I have had the gauges drop out while driving and come on again a few minutes later. I've also noticed today that the radio is on, but the speakers are getting no power. Grrrrrrrr!!

Anyone know where the loom for the instruments begins? There is power at the trip computer fuse and everything after that should be on with the ignition on is dead.

Thanks

Bruce

 

ide imagine the ignition source of the trip would come from the gauges that is probably fused after the switch (could be before, doesnt really matter). the first thing ide do is clean and check all the fuses, even if you have in the past. the best way to check them is with a check light (one end to ground ie the ignition key and the other checking each side of the fuse for power). ive seen plenty of cases where the fuse holders get a little corrosion on them and put a serious spanner in the works. even just rotating the fuses in the holder will clean them enough to make contact sometimes. its best to go along with sandpaper and remove each fuse and clean the fuse itself and the contacts. once thats all done spray it with some inox or wd40 or whatever to prevent further corrosion.

otherwise its likely a broken or burnt wire or the switch is stuffed. how many k's has the car done?

Regards Jay

 

Jay,
Car has 210,000 k's on it. I have checked the fuses with a test lamp and they are OK at both ends of the connection. By switch do you mean the keyed ignition switch? If so that was going to be my next suspect anyway. Is there any test procedure to check the switch itself?

Thanks

Bruce

 

Looks like the ignition problem may have been a loose connection on the ignition amplifier. I was stuck in a shopping centre carpark today when it decided it wouldn't start for the first time in about a fortnight. I checked the battery connections and the earth strap on the starter, but had no joy. I decided to go through all the connections I could see and the obvious first was the amplifier, and lo-and-behold both connections were a little sloppy and the car fired straight up as soon as I pushed them in a bit. Lucky it was something easily accessible.

I still have no gauges though.....

Bruce

 

Bruce:

You must have a schematic to trace circuits on these and any other critters. S57 is it.
Check online captainjaguarscathouse for it.

You may have to remove the crash pad to acess the rear of the fascia and inspect wires and trace circuits with a meter or test lamp or both.

Check you manual for fuse identification and clean each receptacle as suggested. Fuses can look Ok, but lack continuity. A meter or test lamp can check each one.

Yeah, I like the finger roll fix for fuses. Do it from time to time on the lamp circuits under the bonnet on my car.