Circled in Green: The computer signal to charge, I believe. Is this +12vDC with key-on, engine-off? I would like to check for signal here, without running the vehicle, unless it actually has to be running to produce signal.

Circled in Yellow and Red: What are the purpose(s) of these small wires?

TIA!
-Jim

EDIT: The condition is no charge when running, I have already confirmed continuity on the charge cable to the positive terminal in the boot.

 

There should be two wires to the plug: a white/pink which is at B+ with the ignition in position ii (on), and a slate grey/white one which is the regulator output to the instrument cluster charge warning light. JTIS describes it as at B+ when active, which I take to mean that it should be at ground potential when the alternator is delivering a charge.

The black/brown pair of bolted connections go to the 'suppressor module', which, in our early cars, is close to the A/C receiver dryer. This module is cunningly located to block removal of the alternator from the top.

Here's the relevant part of the wiring diagram from JTIS:

 

connector is

ign

sense

lamp

aka internally regulated

 

Sorry Michealh the B+ is always at battery voltage and the wire shown goes to the live bolt on the starter motor . My 97 did not have a suppressor module

There is also and ignition live and a wire to the warning light ..It will not work if the warning light has failed

 

OK, to put it another way:

The heavy-gauge black feed eyeletted onto the alternator stud is B+ always.

The White/Pink to connector PI50-2 is ignition switched B+ via fuse #5 (10A) in the engine compartment fusebox.

The Slate Grey/White to PI50-1 is the charge warning signal to the Instrument Cluster.

The third 'sense' connection to the boot/trunk fusebox didn't arrive until the 4.2L.

The Brown and Black eyeletted pair go to the suppression module, which, prior to moving into the wheel well at some point,
is located here in the earlier cars. Post courtesy of crbass:

https://www.jaguarforums.com/forum/x...5/#post2226915



It seems that they're frequently removed and not replaced for some reason. Probably because the bolts holding the retaining mount are awkward to access.

 

I've read different ways to remove this, including removing the oil filter and/or squeezing it out thru the air box area. But the key for me was removing the radiator fan assembly, with two plugs and two clips (both accessible from the top of the engine bay) & two 10mm nuts, it's not bad at all.

For anyone struggling to remove the alternator from an XK8, here's what I did:

• Disconnected the battery (of course)
• Removed air box and duct up top
• Removed radiator cooling fans (it's easier than it looks & gives a LOT of working space)
• Drained and removed upper & lower coolant hoses (unrelated to the alternator, but they were swollen and looked like they should be replaced)
• Removed serpentine belt
• Jacked up passenger side front
• Disconnected the plug, main wire nut, and suppressor wire nut (8mm) from rear of alternator -- tight but doable, without removing the oil filter.
• Disconnected lower alternator bracket bolt
• Disconnected upper alternator bolt, slide forward, up and out (be careful not to ding the radiator fins)

 

It comes out through the air box hole easy.

delete from your list.....you dont need to remove hoses or the rad fans just the bracket under the air box

 

Maybe that's why it would be easy for you.

 

Does not affect it

 

Keep it civil, friends. No need to get off track from such a great discussion.

Cheers,

Don

 

Hello-I am trying to rewire the alternator plug "Denso Oval" on my 1997 Jag XK8 Coupe. The plug has three connections, I have two wires. I have a gray wire which was on top of a White wire. I guess the bottom contact is not used???? Please help if you can. Thanks for the info here!

 

It comes out through the air box hole But not easy. No room to spare in fact. Had to pound mine upward from the bottom as the unit was frozen into the bracket. Used a two by 4 and a sledge to break her loose. Then shoe-horned up through the air box hole after removing the bracket and suppression module, I guess it is called.

 

sense and dummy light that’s it

 

I removed mine also via the air box. I recall also haveing to remove the oil filter to get to the bolts. The biggest issue I had was freeing the alternator from the mounting bracket. It took a little brute force to get it out.

 

Hi Paintxpert,

The alternator wires are identified in the Electrical Guide. You can download a copy at the link below, courtesy of our forum member motorcarman, who provided the document, and Gus, who hosts it on his website, jagrepair.com:

Jaguar X100 Electrical Guide 1997

Cheers,

Don

 

Hi Don!!! Thanks for getting back! Kudos to Motorcarman and Gus for the electrical guide. You guys are absolutely "invaluable" Related to keeping these Stunning cars on the road!
Couldn't believe a stupid Alternator could put up such a fight. When I ripped the broken plug out I didnt know it was a three pole connector. Surprise!
Now I am waiting for the "Denso Oval" and I hope this chapter is over. Now the big question is should I send my original back as a core??? I am hearing these Denso Rebuilds can be problem some. It is an 80 dollar core. But it is also the ORIGINAL. Thanks Again you guys! Stay well! Regards, Ben PS I hope this is me soon, cruising in my Jag!

 

Jagrepair.com!!! What a concept! Thank-you Gus! Just like the Wizard of Oz. It was there the whole time!!! All I had to do was tap my Heals together! Just like Dorothy! Thanks you guys!

 

Just a note: if someone removed the Alternator from the bottom, I don't know how. Use a sledge, and 2x4, from the bottom if it wont budge. (I know, that hammer can be useful.) The fans do NOT have to come out. Remove Filter (suppressor) bracket. My navigation sends me in the WRONG direction at times, that is a fact. Five cars for 55 years has taught me always to double check. Its like looking twice before pulling out. Cant hurt! God Bless this forum, very organized (Good Moderators) a WEALTH of information.