D

DeanV8

New Member
Good evening all,

Apologies my first post is asking for help, but having a bit of an emergency with my 2004 RR 4.4 V8. Was driving yesterday when dash suddenly lit up like a xmas tree and car clonked into a high gear (think it was 4th) making it seem that power had been lost. Error messages on dash at this point were -

Battery warning lamp
Air Suspension Inactive
HDC Inactive
Trans Failsafe Prog

I realised almost immediately that all these faults at the same time were unlikely and far more likely to be electrical gremlins. The battery warning light was the obvious contender, I thought a low voltage would throw out all the sensors. So after calling out help we replaced the battery but everything was exactly the same.

So we checked voltages at new battery -

Ignition off - 12.8v
Engine running - 15v
Engine running with 3,000rpm - 17.8v and climbing

So my only thought at this stage is a faulty alternator, with the regulator no longer restricting voltage to the max 14.5v that I've read in the manual.

BUT before I shell out what appears to be huge money on a new water cooled alternator (LR actually wanted £1200 but pattern part is better at £400) is there anything else other than the alternator that could be causing this over voltage issue?

Thanks in advance for any assistance
 
Rectifiers are a available as a separate part, track down a good auto electrician and get a quote to repair
 
Having just repaired a motorcycle alternator problem recently, the alternator produces a voltage of around 80 Volts I think and it is the rectifier that governs the voltage to a maximum of around 14.7 volts to stop it cooking the battery so i would imagine it's the same on the range rover, although the rectifier would most likely be integral to the alternator where on the bike it was separate.

You could email the company on the link below, they are German like your Range Rover :)

http://www.alternator-parts.com/
 
Not rectifier pack. Voltage regulator needs looking at. Rectifier does not control voltage it converts AC output to DC.
 
As long as it's only the alternator's internals governing voltage output I'll pull it out today and get it exchanged. Fingers crossed
 
Well things have taken an interesting turn this morning. Went out and the battery is completely dead (5V). Bearing in mind I left nothing on yesterday then something is draining the battery with the ignition off.

After a bit of research it would seem the final stage resistor is a common problem and can cause problems with low voltage.

So I'm thinking that it's unlikely to be a faulty alternator and a faulty FSR at the same time and clearly a faulty alternator wouldn't discharge a battery would it? So now I'm thinking replace FSR first and see if it solves anything?

What are your thoughts?
 
DeanV8 said:
Well things have taken an interesting turn this morning. Went out and the battery is completely dead (5V). Bearing in mind I left nothing on yesterday then something is draining the battery with the ignition off.

After a bit of research it would seem the final stage resistor is a common problem and can cause problems with low voltage.

So I'm thinking that it's unlikely to be a faulty alternator and a faulty FSR at the same time and clearly a faulty alternator wouldn't discharge a battery would it? So now I'm thinking replace FSR first and see if it solves anything?

What are your thoughts?
Click to expand...

Yes if a diode in the rectifier is leaking back.
 
Diode in the alternator? Yeah that would make sense too.

I've got the blower resistor out, it's a cheap pattern part. Will change that at the same time for a genuine part as I have heard a fan going with the ignition off before so it's probably for the best to be safe.
 
wammers said:
Not rectifier pack. Voltage regulator needs looking at. Rectifier does not control voltage it converts AC output to DC.
Click to expand...
That's where i was getting confused, on the bike, the component referred to as the rectifier was also the part we were told to change if it was showing over 14.7 volts but i guess it was doing both the dc conversion and the regulating of the voltage, I will refer to it as the magic box thingy from now on :)
 
I've got stuck trying to get the fan off to make some space to remove the alternator.

FSR replaced with genuine, so some progress at least
 
I did read that thread but making it is far harder than buying one which is what I've done. Hopefully here tomorrow
 
Just an update guys. Changed the alternator over and fired her up and all working great. Steady 14.3v from the alternator. So that is a definite fix for that issue.
 
Good news , well done on closing off the thread, nothing worse than finding a thread with the same issue as you are trying to solve and then no conclusion :)
 
You must log in or register to reply here.

Similar threads

R
P38 Alternator Fault
Replies
2
Views
524
Datatek
Datatek
L
Disco 4 (LR4) battery light on
Replies
9
Views
1K
Graculus
Graculus
dag019
Alternator failed - how to safely continue driving
2
Replies
22
Views
1K
tottot
tottot
T
Voltage stabiliser
Replies
0
Views
393
t.g0r
T
K
L322 Seeking help - Gearbox Fault
Replies
7
Views
812
KCTippi
K