alternator test voltages
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
I don't know what pin goes to the pigtail sense wire on yours... but if you are getting 12.7 and you got the sense wire going from panel to alternator...
It is the panel.
There are specialized shops that just fixes / repairs / rebuilds instrument panels --- go to them to bench test your panel.
Hey --- long shot... do a complete reset of your cars computers --- just in case it is a electronic glitch.
It is the panel.
There are specialized shops that just fixes / repairs / rebuilds instrument panels --- go to them to bench test your panel.
Hey --- long shot... do a complete reset of your cars computers --- just in case it is a electronic glitch.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
I know this is going to sound idiotic ---
If you have a removable Alternator warning bulb --- and you say the bulb is good?
Replace the bulb and base with a brand new one before you rebuild the panel.
On my truck, the plastic bulb bases and the metal insert have worked loose and failed to make proper contact with the PCB on the panel.
So the bulb can test good, but the base being bad mean bad contact.
Eliminate this issue before you go further.
In my case, I took a pair of pliers, and rebuilt each base's metal fittings to ensure it made a snug fit with the bulb and panel.
Then I cleaned the panel PCB with a rubber eraser.
Or just replace the bulb base and bulb with a new one...
It is a long shot... but...
If you have a removable Alternator warning bulb --- and you say the bulb is good?
Replace the bulb and base with a brand new one before you rebuild the panel.
On my truck, the plastic bulb bases and the metal insert have worked loose and failed to make proper contact with the PCB on the panel.
So the bulb can test good, but the base being bad mean bad contact.
Eliminate this issue before you go further.
In my case, I took a pair of pliers, and rebuilt each base's metal fittings to ensure it made a snug fit with the bulb and panel.
Then I cleaned the panel PCB with a rubber eraser.
Or just replace the bulb base and bulb with a new one...
It is a long shot... but...
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 108
Likes: 0
From: Canada,Ont.
Ill give it a go .....but im not getting too carried away this electronic board tampering is very new to me
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Um -- there is no board tampering.
The alternator warning bulb (if your panel uses one) should be in a plastic holder and clearly visible once you remove the instrument cluster from the car.
It is the same as the lights that light up the panel (at night) and turn signal, high beam, etc.
Go back to the circuit diagram, and you will see the alternator light / resistor is needed to "load" the circuit, hence the 8-9 volt and not full battery voltage.
If the bulb is working but intermittently not making contact.. it can cause all sorts of issues.
I am not absolutely sure that your panel uses an alternator warning bulb --- as some panels now use an LED for that.
So this whole issue may be moot.
There is no "tampering" inside the cluster... don't do that!
The alternator warning bulb (if your panel uses one) should be in a plastic holder and clearly visible once you remove the instrument cluster from the car.
It is the same as the lights that light up the panel (at night) and turn signal, high beam, etc.
Go back to the circuit diagram, and you will see the alternator light / resistor is needed to "load" the circuit, hence the 8-9 volt and not full battery voltage.
If the bulb is working but intermittently not making contact.. it can cause all sorts of issues.
I am not absolutely sure that your panel uses an alternator warning bulb --- as some panels now use an LED for that.
So this whole issue may be moot.
There is no "tampering" inside the cluster... don't do that!
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 108
Likes: 0
From: Canada,Ont.
I took the bulb out and and put 12v to it and it lite when the bulb reinstalled to the board and plug in to the battery voltage koeo the output is battery voltage at the output pin and both sides of the indicator bulb is battery voltage , I must be doing something wrong if the bulb is the only resistor in the circut.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Well, we hit dead end.
If you are SURE you measured the alternator exciter wire pin out on the instrument panel (and with the harness disconnected) and it reads battery voltage...
It is time to get that panel to a pro to look at it...
If you are SURE you measured the alternator exciter wire pin out on the instrument panel (and with the harness disconnected) and it reads battery voltage...
It is time to get that panel to a pro to look at it...
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 108
Likes: 0
From: Canada,Ont.
Ive been over wiring schematic a dozen times for the correct pin Im sure Im got it right.....I have caused myself alot of headaches jumping to conclusions an $$$$ so I hope I got it right
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
One technique to try -- leave the harness on (and risk the fault is further downstream) --- but use a probe to check the wire coming out (rather than just the pin).
You can ID the wire by the color --- and be sure you get that right.
If you are at a shop, sometimes it is just easier to substitute a panel... or bench test the panel.
You can ID the wire by the color --- and be sure you get that right.
If you are at a shop, sometimes it is just easier to substitute a panel... or bench test the panel.
Thread Starter
|
Senior User
Joined: Aug 2005
Posts: 108
Likes: 0
From: Canada,Ont.
well I put another board on and same results were found I would like to know in fact that when 12.00v goes into the inst. board that 1-3v would come out of the board to the alternator Im doubting that its the board.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Owch.
Something is really not right.
Is there something downstream connected to the wire that is "live" with 12v?
Wild and crazy idea:
Is there something UPSTREAM of the panel that is giving the wire that voltage?
Something is really not right.
Is there something downstream connected to the wire that is "live" with 12v?
Wild and crazy idea:
Is there something UPSTREAM of the panel that is giving the wire that voltage?