Nobody can work it out!!

[WHEELZ]

Hi All,

Hoping someone here can help as neither my local auto sparky nor my usually awesome mechanic can work out what is wrong with my Jeep!!

2007 XH Commander 4.7L V8 Petrol

Had an alternator get extremely hot and the car stopped dead, the battery had been drained also. Removed the alternator and took it to the auto sparky, he informed me the diodes were shot and it needed replacing. He got me a new one and when I went to install it I noticed the plug where the wires plug into was different. He assured me he would simply change the plug end on the car and all would be good.

Fitted the new alternator and auto sparky came to replace plug end, after this the car wouldn't start due to being in fault mode. Reset fault codes and car started perfectly, then within 10 seconds the battery light came on and fault "no charge" seen on the scantool. Testing with a volt meter showed no charge going into the battery...

Took car to auto sparky who spent weeks trying to work it out, ending in "I have no idea"...took it to my mechanic, he tested all wiring, ecu and earth and all were fine...he spoke with a couple of others and although not certain suspects either this is the wrong alternator, it is stuffed or the wiring on the new plug is wrong (which may be what has stuffed the alternator)...

He too now has given the car back, still with the problem and suggested taking it to my local Jeep dealer...here is the problem!!! My local dealer is a total thief and this will cost nearly what the car is worth if I leave it with them to diagnose...

If anyone has any ideas as to what may be at fault it will be greatly appreciated!!!

Thanks

[Billnick]

Have you tried a different charged battery? A stuffed battery will (might) display those symptoms.

[bjm]

Has your sparky still got your old alternator, if so refurbish it and replace with new diodes ,not a hard task for a good sparky. Also was the new alternator a chinese unit, had similar issues with a cheap /new alternator I put on my boat.
A good sparky shouldn't take weeks to figure out the problem !!!

[rang0]

Do alternators even have diodes? A diode allows the current to go one way. Did the old alternator over charge? I welded to a chassis on a patrol and i had a similar problem afterwards because i didnt disconnect the battery.
The main component to a alternator is the voltage regulator and that is all you need to replace when you have a alternator stuff up you dont need a whole new unit. You need to find out whether the ecu controls the voltage or it has a regulator (brushes). Your more than likely going to have a corrosion issue some where or a broken wire.

Sent from my SM-J100Y using Aussie Jeep Offroad mobile app

[ausjeeper]

Check this out:
http://www.quadratec.com/jeep-replac...lternators.php

[silycr]

I'd suggest either getting the sparky to put the original plug back on,
and take the car to the stealership and get them to sort it(pricey but done)
or source a used replacement alternator as this should have the same plug
or get hold of a wiring diagram and locate the correct colours for the alternator wires and confirm they are going to the right place yourself

with any of those option, I would get the battery tested. Supercheap tests them free if you ask

[layback40]

Originally Posted by rang0

Do alternators even have diodes? A diode allows the current to go one way. Did the old alternator over charge? I welded to a chassis on a patrol and i had a similar problem afterwards because i didnt disconnect the battery.
The main component to a alternator is the voltage regulator and that is all you need to replace when you have a alternator stuff up you dont need a whole new unit. You need to find out whether the ecu controls the voltage or it has a regulator (brushes). Your more than likely going to have a corrosion issue some where or a broken wire.

Sent from my SM-J100Y using Aussie Jeep Offroad mobile app

1/ All alternators have diodes. Thats how they produce DC.

2/ Jeeps dont have regulators in their alternators, they have the function of a regulator done by their ECU.

This problem sounds like it started as a bad short in the alternator. Thats probably why it got hot. The alternator may have then fried the ECU.

A good sparky could diagnose what is going on. An average sparky would just start replacing bits until the problem goes away.