In the diagrams below the diagrams provide a nice map and key for all/many of the important grounding points for my 1990 Jaguar XJS Convertible ... I'll be going after as many as can find with a dremel this weekend.

In the ground point diagram, all of the ground points give a nice description of where they can be found BUT some (see pic) are simply labeled "B"! Where the hell is, "B"?

The reason I'm needing to do this is that on start up my dash volt meter takes a while to climb to "normal "... some squealing... on driving when applying the brake with lights on, V meter drops real low. With climate control fans on,,, forget about it. Low voltage and squeals from alt. Gotta fix it.

SIDE QUESTION _ does anyone know where (see pic) the "EFI Main SW Relay" is located and what its basic function is?

As usual... deep bow and many thanks,,, in advance

Sample... Notice ground lines ending in \"B"...

Ground point diagram.

 

The main relay (or at least one of them) is in the boot, just under a cover on the RHS above the battery on the side panel. It has the fuel relay next to it, and a larger electronic thingy usually with a label saying V!" on t - this last is the interface unit for the trip. If your car is powering up when the key goes to ignition, it is working. see pic

 

JJJ,

A squeal under electrical load just sounds like the alternator belt needs retensioning or replacing.

The "B" on the earth wires diagram probably is just indicating the wire colour.

Cheers

Paul

 

I'll check the belt, it's new. The alternator is new-ish. When the needle is at normal I'm getting 13+volts at the battery and bar along the firewall... I know cleaning grounds is a plus plus 10 necessity on these machines - but yes I will recheck the belt. I have also placed an Earth strap from the alt directly to the chaise...

Which brings me back to my original blabbering... Many of the gound points (which I can agree will mean BLACK where there is a B) in the schematic(s) in the manual do give a specific location for MANY/MOST of the termination points of a ground line. But, in some cases, it does not. It gives the B (indicating color in a way different to other lines in schematic) but does not say WHERE in the vehicle to find that terminal ground point... I need that information and I'm wondering (if not labeled) what should I understand about that terminal points that are not labeled??? Where are they??? I do... I need to try to clean and freshen all of these points,,, or as many as possible.

 

You can probably get away with regrounding the engine at the Alt mount bracket to where ever depending on length of cable, and add another ground from dash to body. I did this it had a noticable effect particularly on gauge response time.

 

Thanks Van... I've done this/that at the alt... In general,,, where on the dashboard?

From the diagram, how would you chase ground points that are not labeled?

 

There is a metal bar along the back/top printed circut board I believe thats where I did it, I'm sure someome else can confirm. As for chasing wires I don't know, there are tools to trace wires but again I'm no electrician

 

The following grounds (earths you must call them now you smoke Gold Block) are easy to get to:

• In the trunk (boot, ditto) underneath the ECU/relay area on the chassis rail
• In the engine bay: each side of the radiator top closing panel, under the rearmost fixing bolts
• The engine earth from the LHS of the sandwich plate via the subframe to the lower chassis rail (your extra alt earth will help anyway)

These are not easy to get to and require the dash/centre console to be removed: on the windscreen vertical strengthener metalwork, each side of the aircon unit, various odd places under the console.
I really would not worry too much about these until and unless you have a specific problem.

 

Hello JJJ

Just a side question - you have said that you have installed a new(ish) alternator recently - how many amps is it, ie - is it big enough to run everything in the car?

I don't remember if you are running electric fans, but these draw a lot of amps, along with air con, all the other electrics, If your volt meter takes a while to normalize, maybe your alternator is not big enough.

I have a 100 amp Alternator in mine

Cheers
Steve

 

Smart question,,, so I just went back and looked at the listing. It wasn't available for the full viewing (it was a used alt). It did jog my memory tho. It was/is a "tested at 115 or 120" Bosch alt... I remember looking at a bunch at the time knowing that I wanted a higher amp rating. I will test for amps and see what's actually happening with it.

QUESTION - Will a Lithium Ion battery improve the low voltage? When I started working on Cherry,,, just to have a battery,,, I spent as little as I could on a new battery, new, but cheap...

 

Simple answer NO. LI batteries need a different charging system. I would not use LI on a SLA charging system. Just put the biggest battery that fits. I did this and my car starts first time every time.

 

That's better...

Dremel on all ground points, most relays, most(many) electrical connections etc - couldn't get to grounds as listed in the diagram behind dash - any pointers welcomed...

This is with fans on high and high beams on...

 

The earths (!) on the dash supports cannot be reached dash in car. Never mind, you have done a great job, impressive volts.

 

Hello JJJ

Again - 10 years older than yours - but this is the earths that I have found behind the dash.
I removed mine due to a failed ignition switch (could not get the key in the barrel).
Then had to remove the steering column because I could not get the anti theft screws holding the ignition to the steering column.
Then I figured I would remove the fascia due to two cracks being in it.
Then I figured that while the fascia was out - I would put in a new air conditioner unit.
Due to the new air conditioner needed to be done by a certified person in Australia, I need to take the car to their workshop, which means I need a lockable vehicle. (which I still don't have).
I could go on - but lets just say my wires are easily workable at the moment - which has its advantages.


Cheers
Steve