Charging problem
Thread Starter
|
New User
Joined: Feb 2007
Posts: 10
Likes: 0
Charging problem
I have a problem on a 03 F250. My charge light is on in the dash. I changed the alt. and still have a light.
I cked the voltage on circuit 904 LG/RD. I have 12 volts key on engine off & 2 volts with the harness pluged in to the alt. I start engine with no change. I jumpered circuit 35 and 904 and the alt. did not start charging
Is my new alt bad? How do I ck. The alt. on engine?
I cked the voltage on circuit 904 LG/RD. I have 12 volts key on engine off & 2 volts with the harness pluged in to the alt. I start engine with no change. I jumpered circuit 35 and 904 and the alt. did not start charging
Is my new alt bad? How do I ck. The alt. on engine?
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
I have a problem on a 03 F250. My charge light is on in the dash. I changed the alt. and still have a light.
I cked the voltage on circuit 904 LG/RD. I have 12 volts key on engine off & 2 volts with the harness pluged in to the alt. I start engine with no change. I jumpered circuit 35 and 904 and the alt. did not start charging
Is my new alt bad? How do I ck. The alt. on engine?
I cked the voltage on circuit 904 LG/RD. I have 12 volts key on engine off & 2 volts with the harness pluged in to the alt. I start engine with no change. I jumpered circuit 35 and 904 and the alt. did not start charging
Is my new alt bad? How do I ck. The alt. on engine?
What are those circuits?
2 volts? is that a mistake?
See alternator diagnostics link below.
Thread Starter
|
New User
Joined: Feb 2007
Posts: 10
Likes: 0
Charging problem
The circuits I tested were to the voltage regulator on the alt.
Yes 2 volts was Correct. The manual says this is normal for Key on engine off voltage. The voltage should come up to 8-9 volts after the eng. starts.
After i changed the alt I cked. the voltage at the regulator. The GN/RD wire or (I) wire had 13 volts. The Book says that should have had 8-9 volts. The OG/LB wire (sensing) had Bat. Voltage (14 Volts). The alt worked fine for a couple days. Is it possable there is a problem with the PCM putting putting to much voltage (13 V) to the regulator and frying the reg.
Also if I put 12 volts to the GN/RD wire (I) on the regulator. will that bypass the trucks wiring and rule out a bad alt. as the problem?
Yes 2 volts was Correct. The manual says this is normal for Key on engine off voltage. The voltage should come up to 8-9 volts after the eng. starts.
After i changed the alt I cked. the voltage at the regulator. The GN/RD wire or (I) wire had 13 volts. The Book says that should have had 8-9 volts. The OG/LB wire (sensing) had Bat. Voltage (14 Volts). The alt worked fine for a couple days. Is it possable there is a problem with the PCM putting putting to much voltage (13 V) to the regulator and frying the reg.
Also if I put 12 volts to the GN/RD wire (I) on the regulator. will that bypass the trucks wiring and rule out a bad alt. as the problem?
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Do an output test by measuring voltage and current from the alternator at, say, 1,800 rpm.
Turning on everything electrical (headlights, AC, fan, etc.) to raise the electrical load.
See what current is coming off the alternator.
If voltage is substantially below 14v, and current is low... then you have an issue with alternator output.
Work backwards, first to field winding power.. if that is OK, then you are down to bad alternator.
Test batteries while you are at it too.
Turning on everything electrical (headlights, AC, fan, etc.) to raise the electrical load.
See what current is coming off the alternator.
If voltage is substantially below 14v, and current is low... then you have an issue with alternator output.
Work backwards, first to field winding power.. if that is OK, then you are down to bad alternator.
Test batteries while you are at it too.
Thread
Thread Starter
Forum
Replies
Last Post
garydmundy
1999 - 2003 7.3L Power Stroke Diesel
5
Nov 25, 2013 09:45 AM
