I own a 1994 Jaguar XJ6 it recently stopped charging the battery I replaced the alternator and the alternator suppressor but battery still not charging any advice on what to fix next would be greatly appreciated

 

Welcome to the forum AmericanSwag83,

I'm sorry to hear about the charging issue.

I've moved your question from Jaguar Forums Advice / Feedback & Suggestion Center to XJ40 forum. The Advice / Feedback & Suggestion Center is for posts about the forum and not for technical questions.

Members here with the same model will be able to help.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

There are a few wires connected to your alternator. First of course the big lead to the starter. Then there is a connector with two wires (white/green and white/yellow from memory).

One of them will get 12v after ignition, again from memory I think it's the white/yellow one. The alternator needs this 12v to build up the electrical field to generate power. So when this wire won't get 12v the alternator will not work. The other wire is for the lamp on your dashboard. This one gives a 12-13.5 volt signal when all is working fine, after starting the engine.

I hope I am clear.

The wire that gets 12v, after ignition is powered through the center fuse box. So check your center fuses as a first step. If these are fine, Measure if one of the thin wires has 12v after ignition. If not, the wire is most likely cut or damaged somewhere.

 

Thank you all I will check these wires best site ever

 

Hi AmericanSwag83,

Wilfred has given you some good things to check. The fact that you've replaced the alternator would seem to rule out a failed rectifier diode, so...

Most major auto parts store chains (O'Reilly, AutoZone, NAPA, etc.) will run a basic evaluation of your electrical system for free, so that would be worthwhile to rule out any obvious problems. It may be that your battery has given up the ghost and will no longer hold a charge (Jags tend to be very hard on batteries). It may also be that you have a parasitic drain that is drawing down the battery (examples include a relay that is not unlatching, an interior lamp switch that is stuck ON, etc.).

On our '93, we had poor battery charging until I went through the entire car and cleaned every battery power connection and ground point and repaired cold solder joints on all three fuseboxes.

Below are links to photos of all the battery power connections and ground points throughout the car. Oxidation on the wire terminals, nuts, star washers and threaded studs can add cumulative resistance to the circuit (the resistances of all the connections added together become significant).

Battery Power
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Grounds
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Fuseboxes
Welcome to Jag-lovers - Members Photo Viewing Page

If an electrical system test and Wilfred's recommended checks don't turn up any problems, it might be worth cleaning all the battery power connections, and at the very least the grounds in the engine bay (including the engine ground strap), the grounds at the A-pillar fuse boxes, and the negative battery power cable-to-body stud. The other grounds and fuseboxes are well worth servicing as well.

Cheers,

Don