charging system problem
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charging system problem
I know there are a lot of threads about charging system problems, but I have not found one that had the info I need to trace this issue, so...
Truck 1999 F250, 7.3 powerstroke
problem charging system light (the battery light) started to come on at low rpm, but went away at higher rpm
tested alternator output, it was a little low 13.1 volts so replaced the alternator
new alternator, charging light came back on at low rpm then went away at high rpm, but the rpm that caused it to go away kept getting higher untill it stayed on constantly
replaced batteries, they were under waranty and a little low on cranking amps
output from new alt is 14.5 volt and batteries are new, but charging light still on
field wire on alt is at 12.5 volt, "I" terminal on alt is at 1.5V with key on and engine not running it stays at 1.5V with engine running, and I thought this was supposed to go to 12V with engine running?
I have checked all fuses, and as much wiring as is possible without tearing everything apart, nothing seems to be shorted to ground so what can I test next?
Truck 1999 F250, 7.3 powerstroke
problem charging system light (the battery light) started to come on at low rpm, but went away at higher rpm
tested alternator output, it was a little low 13.1 volts so replaced the alternator
new alternator, charging light came back on at low rpm then went away at high rpm, but the rpm that caused it to go away kept getting higher untill it stayed on constantly
replaced batteries, they were under waranty and a little low on cranking amps
output from new alt is 14.5 volt and batteries are new, but charging light still on
field wire on alt is at 12.5 volt, "I" terminal on alt is at 1.5V with key on and engine not running it stays at 1.5V with engine running, and I thought this was supposed to go to 12V with engine running?
I have checked all fuses, and as much wiring as is possible without tearing everything apart, nothing seems to be shorted to ground so what can I test next?
Lead Driver
Joined: May 2003
Posts: 9,303
Likes: 48
From: Lyndonville, Vermont
The Lg/r wire is the wire that shuts off the light on the dash. this wire should be 12v or higher to shut the light off. If not it may be a bad regulator or connector. The O/LB wire goes though a 10 amp fuse back to the battery though a fusable link. The bk/O is the big wire. Check all connections first...And fuse number 6.
No other alternators in there is there. they hide...Dual
Dick
No other alternators in there is there. they hide...Dual
Dick
Last edited by 99f350sd; Feb 9, 2007 at 03:39 PM.
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
As I was told while diagnosing my $800 alternator, that plug is very difficult to fully seat. Another critical connection is the alt case to bracket. The Alternator gounds to the bracket, to the motor, to the frame and then to the battery. So check your voltages at the alt case and the batteries.
Junior User
Joined: Dec 2006
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Had a similar problem on my 2000 sd.Changed the battery and atlernator and it didnt help.Found one of the wires comming off the solenoid had a factory splice that when I opened it up the wires were green and broken apart.I cant remember which wire it was but it came off one of the studs and was within a foot or two of the solenoid,check carefully as it had shrink wrap over it, but I installed a new wire with a ring terminal to the solenoid and never had another problem .Hope it helps Jason
Lead Driver
Joined: May 2003
Posts: 9,303
Likes: 48
From: Lyndonville, Vermont
Originally Posted by ReAX
no, I wasn't happy with the manufactures of the 200 so I found a 230 amp.
Dick
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New User
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got it fixed, the replacement alt was also bad with same symptoms as the first
what confused me was that it was charging, just the battery light was on, I guess the internal sensor circuits were bad on both alternators not giving 12v to the dash
what confused me was that it was charging, just the battery light was on, I guess the internal sensor circuits were bad on both alternators not giving 12v to the dash
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