Hello I have a 1993 Ford 8000 with a 8.3 Diesel and it will not keep charging the batteries. Have two new batteries, new alternator. Will charge for about one minute 14.1 volt then stops charging, if you turn ignition key off and then back on again it will charge for a another minute or so. Did the same thing with the old batteries and old alternator. Any ideas. Thanks in advance Jon
Behind the air cleaner is a voltage regulator.... unplug it and jump the two wires on each end of the plug in.... if it stay's charging its your voltage regulator.
Wow that was fast will try first thing tomorrow. Thanks Grandpa
No problem Jons.... let us know what you find.... and welcome to the forum.
Just dawned on me truck is a L8000 not a F. Jon
No problem.... the advice was for an L
Ok looked at truck no regulator behind air cleaner. What about ignition key switch. ??
I'd continue to look for the regulator, that's your most likely suspect. Just to clarify, are you reading your power output with an independent meter or from the dash gauge?
93 should have internal regulator in alt. Check voltage at batteries or alt, volt meter in dash runs through cab harnes and relay
I don't think it would be the ignition switch because it starts charging... switch wouldn't make it stop in most instance's.
Reading output both at gauge and at batteries, when gauge drops back after one minute voltage at batteries goes from 14.2 to 12.97 so gauge is showing the drop, also if lights are on you can see the drop in voltage. Cant find a regulator on firewall. Where would the relay be located. Picked up new ignition switch thought would try tomorrow.
are you using a remanufactured alternator by chance? A lot of times they just do a point of failure repair and a paint coat...
12.97 is still charging, at idle with lights on might be normal. My L8000 shows every light you turn on drops volts on gauge, what about at 2000 rpm?. Relay is under dash on mine 1988.
No when quits charging it quits, only 60 to 90 seconds after starting makes no difference of rpm at 2,700 still no charge. If you flip key off and back on starts charging for 60 to 90 seconds, I have fuel shut off disconnected so motor does not shut off when you cycle ignition switch. Has done this same thing with two alternators the original one and the reman. It will run batteries down if you have lights and heater on after one hour or so. This relay what would it look like. Will look again tomorrow will hold off on ignition switch which I can return.
Did you have old alt checked? What about checking to see if wires on alternater are hot. One big one is hot all the time and there should be a wire that is energised by the switch. I would check them with it charging and after it quits.
Old alternator used to do same thing and finally failed so had it rebuilt. Wondering if should take back and have shop check output for a couple of minutes to see if it has a internal regulator, and that is acting up. ??
Would be as good as place as any to start. That relay you would be looking for is above and to the left of the heater control box. Its usually a little chrome looking thingy...lol... kinda hard to get to, but it can be done...
Ok put alternator on bench stays charging fine. Something that I have overlooked is this truck has a alarm system that shuts down if high temp, low oil pressure, low coolant level. I now think the 60 to 90 seconds has something to do with that, If I hook the fuel shutoff up that shuts down the engine at the 60 to 90 seconds also. Any one know anything about the alarm system. Think its a Kyser ?
I don't think that's the problem.... did you ask if this alternator has a built in regulator?
Built in regulator none on firewall, alternator puts out 14.0 plus volts on test stand for as long as you run it. Forgot about the Kysor engine shut down and alarm system that's why I disconnected the fuel shut off it would shut off engine every 60 to 90 seconds, but with it disconnected can still run truck but lose voltage.
Did you look for the relay that sit's below the dash?
How big is this relay and what would it look like, I have a row of four relays in near some fuses. ?
This would be square,,, about the size of a signal flasher( the square one's) but its not under the dash door for the fuse's. Its below that door and to the left. You can actually leave that dash door closed . Then look to the left , above the heater, back in aways. It will have a plug in on it with two maybe three wire's to it.
Have a JCB that had the same problem,two new batteries and new alternator I was pulling my hair out till I got hold of wiring diagram, showed a switch that excited the alternator when it sensed a voltage drop which was in the ignition switch wiring,simple 30.00 part fixed the problem. Just a thought.
Thanks for all the help I'm sure will find it in time. Will find the part grandpa told me where to find first, then on from there. Hoping that's the problem we do hear something in that area click when we lose voltage. Hope everyone had a safe New Year and a great 2014 Jon
Hello grandpa what do you call this relay when I find it and ask at the ford truck center.?? Thanks again.
I have a 89 l9000. The voltage regulator is under the hood mounted on the firewall on the passenger side.
Ours is a 1993 with 8.3 Cummins, cant find anything on firewall, alternator shop man that have used for 25 years says its built into alt and was replaced last week. Thanks Jon
I would replace relay. But it sound funny that a bad relay would work the same every time. If it has some thing on it that is a alarm that is shuting it down and you are runing it with the pump shut off not going that is were i would look.
Take it off (only has one bolt) take it to a Napa or similar store, its a pretty common relay.... cheaper there than Ford.
Its in your alarm system when its killing power to your fuel solenoid its also killing the power for the alternator exciter
Any idea how I can disconnect the Kysor alarm system
Maybe I'm wrong but once an alternator take's excitation its not needed again until you shut it off???? His start's to charge then kicks out.
Ok it's fixed. Did put in new ignition switch, only because it was only $ 30.00 and I had one for another truck but that didn't fix it. We finally found the shut down alarm box duct taped to the back side of dash board with the buzzer taped down so you could not hear the alarm, that took few hours to find after removing all three dash panels and heater covers. Turns out the module has failed and keeps shutting down system and motor fuel and charging. We jumped past the module and fuel shut down works right again and charging system is fine. Alarm system turned out not to be a Kysor but a Multi-Alarm II, Thanks for all the great help. Jon
Will Try to send picture of alarm
Here it is.
Try this again.
Hmmm.... an aftermarket..... well still glad ya got her fixed and told us the outcome.
You are welcome thanks for all the quick help. Jon
I have a 1992 Ford l8000 that is not charging. It is the blue back alternator. I unplugged the external voltage regulator behind the air cleaner and jumped the two end wires, still only charging at 12.4
bryce13, pull the alternater off and take it to a parts store to be tested, then we'll go from there.
Have same issue voltage low and solinoided shutdown valve Keeps turning off can someone send photo where I can find this multi alarm ii
Can’t see it here
Did you figure out the issue ?