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I am having a problem with my batteries going flat overnight. I found my regulator was hot to the touch with everything off and the truck not running. I repaired as seen in the photos but my batteries still go flat? Help. When I turned over my 'Hot' voltage regulator, this is what I found. I stripped and repair all the wires and put in a spare regulator from a 78. Gave me 14.1 v on a dual battery setup while charging.
Sorry forgot to be specific. 91, 7.3IDI, auto 4x4.
Do you have a way to check for current draw? A easy way is to take both negative battery cables loose and set the cable ends on rags so they do not ground out. Then get a simple testlight with just the clear bulb inside it, and put the clip on just one of the battery negative posts, and touch the probe of the testlight to the cable laying on the rag. If the testlight glows bright, you do still have a drain.
Make sure the doors are closed, the domelight will be a drain and foul the test. A radio memory is not enough to make the testlight glow. If you get a bright light from the test light, then take the large stud output connection off the alternator. Then see if you still have a drain by touching the testlight to the terminal on the rag. If the drain goes away, you have a shorted diode inside the alternator.
Thank you for replying. Yes I have attached an 1156 bulb and it does light quite strong. I will do the test of the alternator as you suggested. When the truck is running the charge voltage is only 14.1 vice what I am used to seeing: 14.7. Could this also be an indication of a bad diode in the alternator?
I immediately was concerned that the problem would be related to the 'fried' regulator pin and that the new(er) regulator would fix it! Not so lucky. I will keep hunting.
Thank you for replying. Yes I have attached an 1156 bulb and it does light quite strong. I will do the test of the alternator as you suggested. When the truck is running the charge voltage is only 14.1 vice what I am used to seeing: 14.7. Could this also be an indication of a bad diode in the alternator?
I immediately was concerned that the problem would be related to the 'fried' regulator pin and that the new(er) regulator would fix it! Not so lucky. I will keep hunting.
If it turns out the alternator wire test doesn't work, you can unplug anything you suspect on the truck and see if the light goes out. You can unplug the regulator and see if the light goes out. You can pull fuses and see if the light goes out on any one of them. Like I mentioned though, always shut the door, the domelight will be a load and make your testlight burn.
If it turns out the alternator wire test doesn't work, you can unplug anything you suspect on the truck and see if the light goes out. You can unplug the regulator and see if the light goes out. You can pull fuses and see if the light goes out on any one of them. Like I mentioned though, always shut the door, the domelight will be a load and make your testlight burn.
I will post a response with what I find...Thank you for your help. Dave
I disconnect the Alt Batt line and the light does not go out. It does go out when i disconnect the Org/Bl Field wire at the Regulator. It also goes out when I disconnect the Yel/Wht - Starter Relay wire at the regulator? There is a short video here showing my results.
Make sure you do not have 12v on the green/red wire at the regulator. Most trucks have this wire on the "S" terminal of the regulator, but some have it on the "I" terminal. Find that wire and put a meter on it, + lead to the green/red, - lead to the battery negative. You should not have 12v on this wire with the key off. If you do have 12v on this wire, that is what the draw is, that wire comes from the keyswitch and brings the charging system online to charge. You will have to continue troubleshooting if this wire has 12v with the key off.
If that wire does not have 12v with the key off, I would replace the regulator Good job troubleshooting with the light.
I performed the static voltage tests as per the Ford Troubleshooting guide and also did the resistance measurements of the alternator. The draw does disappear when the Field terminal is disconnected. And with the engine and key off; there is 12vdc on the field wire when disconnected from the Alt. The Ford book says that is a blown EVR. So I have ordered one from Amazon as my local NAPA supplier here in Canada wanted $46. I will post the other results when the EVR shows up next week.
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