voltage regulator?
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Freshman User
Joined: May 2010
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From: DC North Carolina
voltage regulator?
I have a 89 7.3 5 speed
I put 2 new batteries in my truck in the last week or so think they were my problem. The voltage meter(?) in the truck would shoot almost all the way to the high mark. I fidured that is just the way it was supposed to do. Went to go get in the truck this evening. I hit my manual glow plugs and went to turn it over and the batteries were dead. I got out of the truck to go jump it off. I hook it up to the other vehicle and start looking around. The wire that connects to the alternator is fryed completly in 2. the voltage regulator is hot also. I had the alternator checked just last week so I'm thinking my problem is my voltage regulator. Am I on the right track or do I need to look elsewhere? Thanks alot for the help
I put 2 new batteries in my truck in the last week or so think they were my problem. The voltage meter(?) in the truck would shoot almost all the way to the high mark. I fidured that is just the way it was supposed to do. Went to go get in the truck this evening. I hit my manual glow plugs and went to turn it over and the batteries were dead. I got out of the truck to go jump it off. I hook it up to the other vehicle and start looking around. The wire that connects to the alternator is fryed completly in 2. the voltage regulator is hot also. I had the alternator checked just last week so I'm thinking my problem is my voltage regulator. Am I on the right track or do I need to look elsewhere? Thanks alot for the help
Elder User
Joined: Mar 2010
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good chance you are
after you fix that wire get out a volt meter (the $5 harbor freight kind works fine) and post up your voltage with the ignition off idling and at 1500 rpm just measure the voltage acrossed the terminals
but before you buy a new voltage regulator take it off the firewall and clean off the ground point and all the terminals
after you fix that wire get out a volt meter (the $5 harbor freight kind works fine) and post up your voltage with the ignition off idling and at 1500 rpm just measure the voltage acrossed the terminals
but before you buy a new voltage regulator take it off the firewall and clean off the ground point and all the terminals
Postmaster
Joined: Apr 2008
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How big is the main charge wire, 6-gauge? If it's fried completely through then you have a lot of current going through that wire, a whole lot more than the alt itself can produce even at full field. I've heard or diodes shorting out internally in the alternator can cause a sort to ground of the batteries which would burn the main charge wire like that, don't think faulty voltage regulator can cause such a thing tho...
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Freshman User
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From: DC North Carolina
I had the alt. tested and they said it was good. would it still show up good?
How big is the main charge wire, 6-gauge? If it's fried completely through then you have a lot of current going through that wire, a whole lot more than the alt itself can produce even at full field. I've heard or diodes shorting out internally in the alternator can cause a sort to ground of the batteries which would burn the main charge wire like that, don't think faulty voltage regulator can cause such a thing tho...
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Freshman User
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From: DC North Carolina
I looked for melted wires all over the pas. side I didn't see any
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Post Fiend
Joined: Nov 2003
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From: Nutter Fort, WV
What the test showed when they tested it would depend on what they ran for tests.
If they only checked to see if it was charging, then it could test good and still have bad diodes.
If they did a full test, the bad diodes should have showed up.
I have a brand new alternator on my 86 right now.
Charges good, but the bad diodes in it will drain the batteries overnight.
If they only checked to see if it was charging, then it could test good and still have bad diodes.
If they did a full test, the bad diodes should have showed up.
I have a brand new alternator on my 86 right now.
Charges good, but the bad diodes in it will drain the batteries overnight.
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Freshman User
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From: DC North Carolina
do the normal test they do at autozone show the diodes???
I'm not sure I have ever even heard of diodes before. are they internal (the alternator) or external. and is there a way to test if they are my problem (besides taking it to a place that test them)??? also would bad diodes cause my wire to fry??
thanks alot for the help guys. I've never been much of a electrical person, but I'm trying to learn!!
I'm not sure I have ever even heard of diodes before. are they internal (the alternator) or external. and is there a way to test if they are my problem (besides taking it to a place that test them)??? also would bad diodes cause my wire to fry??
thanks alot for the help guys. I've never been much of a electrical person, but I'm trying to learn!!
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Freshman User
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From: DC North Carolina
Ok guys I went and did some reading on the diodes and the alternator. It seems that maybe the diodes are my problem. The alternator and voltage regulator were warm before the truck was even started. I read somewhere on here that that is a sign that they are bad. Would that also explain my wire frying??
Also I have read that some "new" alternators have bad diodes. Can you buy and replace the diodes seperate from the alternator if not, how do I know that the alternator I am getting has a good diodes?? should I go buy it from a certain place or buy a certain brand?? thanks again!
Also I have read that some "new" alternators have bad diodes. Can you buy and replace the diodes seperate from the alternator if not, how do I know that the alternator I am getting has a good diodes?? should I go buy it from a certain place or buy a certain brand?? thanks again!
Postmaster
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AutoZone can run two types of tests, the quick one is what they usually do one because it's faster, and two because IIRC the more thorough procedure requires some add-on equipment for the main testing machine that most stores do not bother to buy. So chances are you got the quick diagnostics and it missed the bad diodes.
When it comes to alternators I prefer the AutoZone ones cause there's an AZ store pretty much everywhere. Then again I don't buy just the cheapest one they got, I usually go for the Duralast Gold reman unit cause it's priced decently and seems to be of decent quality...
When it comes to alternators I prefer the AutoZone ones cause there's an AZ store pretty much everywhere. Then again I don't buy just the cheapest one they got, I usually go for the Duralast Gold reman unit cause it's priced decently and seems to be of decent quality...
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