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electrical question

Old Jan 22, 2009 | 04:11 PM
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From: Perry Georgia
Question electrical question

I have a 1987 F250 6.9 Diesel. When I start to work in the morning, 5:15am The volt meter acts crazy. It will go to the charge side but still in the white and stay there for awhile. Then it will drop back to the discharge side but not all the way do total discharge. It will do this repeatedly all the way to work which is 20 miles. Charge then discharge, back and forth all the way to work. There are no idiot lights at all during this time. On my way home in the afternoon everything works fine. Also in the morning the only electrical stuff running is the lights. The lights don't dim when the volt meter drops and everything seems ok except the volt meter acts up. Any ideas?
 
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Old Jan 22, 2009 | 04:24 PM
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your voltage regulator may be going bad or you may have a short somewere, and does it run the batterys down? and what does it do at night time?
 
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Old Jan 22, 2009 | 05:35 PM
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Could also be a bad ground.
 
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Old Jan 22, 2009 | 05:43 PM
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get a donor and rewire it
 
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Old Jan 22, 2009 | 08:46 PM
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The battery doesn't run down. At night is when I notice the voltage meter going crazy. I watched in this afternoon,3 pm and the meter didn't jump around like it had this morning at 6am. Could the lights be shorting out somewhere?
 
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Old Jan 23, 2009 | 07:33 AM
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it could be a short or a bad ground some were in your head light wires, does your head lights act funny or anything else besides the votage meter?
 
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Old Jan 23, 2009 | 08:03 AM
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Check the main light switch connector for burned up and the light switch for damage to the prongs.
 
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Old Jan 23, 2009 | 03:31 PM
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i forgot to mention that, good thing you thought of that, i had a head light switch problem actually i had it twice, the first time i had the problem i couldnt get the tail lights and head lights to come on together, found a used switch and that fixed it for about 5 months, then it started going out again and i would just be going down the road and the lights would go out. it sucked my step dad almost recked and i almost didi one time.
 
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Old Jan 23, 2009 | 07:55 PM
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I just replaced the headlight switch within the last year. I guess I'll just have to check it out.
 
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Old Jan 23, 2009 | 08:43 PM
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those and voltage regulators my dad always had trouble with on his truck
 
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Old Jan 24, 2009 | 09:52 AM
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This mod will eliminate the headlight switch problem forever.

It uses relays to take the headlight amperage load off the headlight switch and wiring.

https://www.ford-trucks.com/article/...ay_System.html
 
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Old Jan 31, 2009 | 09:08 PM
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Thankx guys I'll check the light switch asap. Today I changed the fuel selector valve and it will be nice to know I have a full rear tank but couldn't get to it without syphening it out.
 
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Old Feb 22, 2009 | 07:20 PM
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Just an update on the electrical problem. I R&R the regulator since I had bought one when I first got the truck. I don't remember why but it wasn't being used so I figured I'd try that first. I changed it and didn't drive it till the next day when it almost pegged the volt meter when I went to go to work. I limped back home so I wouldn't damage anything. I put the old regulator back on to get to work. On my way to work everything worked like it was supposed to. No more problems. I think the connections might have been bad. I know I had a 1977 gasser that would give me all kinds of problems until I unplugged the regulator a number of times and then everything worked fine. Corrosion problems I would guess in both cases. Either way, everything is working fine now.
 
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Old Feb 22, 2009 | 09:16 PM
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Originally Posted by joe f350
get a donor and rewire it
A donor??

As in parts from a truck that might be just as old and could be no better shape than the one being fixed?

Wiring gets old, and if you are pulling and reinstalling old wiring, you just do more damage!

There are companies that reproduce wiring for older trucks, that is assuming the factory no longer offers it as NOS, aka New Old Stock.
 
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Old Feb 22, 2009 | 10:29 PM
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I have found something as simple as removing a connector and the reinstalling it can fix some problems like he was having.

To many connectors have different metals from one side to the other and cause corrosion just from being plugged in.
 
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