Alternator wiring
Thread Starter
|
New User
Joined: Dec 2013
Posts: 2
Likes: 0
Alternator wiring
He guys, I'm getting pretty frustrated. I pulled the engine on my truck to put a new clutch in and had no charging issues prior to this. after putting the engine back in the alternator will not charge. I have taken the battery and alternator to the local parts store and had them tested and they both tested good. When I put them back on the truck and have the guy run an alternator test it says there is no voltage. Any help? It is a 1979 F150 4x4 302 4 spd. There are four wires going to the alternator; Larger black one that goes to battery, orange one coming from F terminal on the voltage regulator I assume goes to field on the alternator, and two paired wires that I am not real sure where to put. One is coming from the "S" and the other "A". I thought it hooked to the stud marked stator. Is this correct?
Moderator
Joined: Jan 2001
Posts: 56,980
Likes: 2,735
From: Virginia
What happens a lot when the engine is pulled out and put back in, grounds are left off. There is a main ground for the cab usually bolted to one of the bellhousing bolts, and then it goes up to the cab firewall.
Did you do a lot of fixing up and painting while it was apart? That causes problems also, all the nice painted inner fenders and stuff don't get a good ground through the newly painted pieces. This includes the ground to the regulator.
If you think your grounds are ok, get a testlight or voltmeter. With the engine off, put the neg lead on the battery, and probe the large output lead on the alternator. You should have 12v there. If not, there is usually a fusible link in this wire that can blow out.
If you get through all this and it still doesn't charge, there are some other things to check.
Did you do a lot of fixing up and painting while it was apart? That causes problems also, all the nice painted inner fenders and stuff don't get a good ground through the newly painted pieces. This includes the ground to the regulator.
If you think your grounds are ok, get a testlight or voltmeter. With the engine off, put the neg lead on the battery, and probe the large output lead on the alternator. You should have 12v there. If not, there is usually a fusible link in this wire that can blow out.
If you get through all this and it still doesn't charge, there are some other things to check.
Thread Starter
|
New User
Joined: Dec 2013
Posts: 2
Likes: 0
I checked the ground behind the engine you are talking about and I am getting continuity there. I just rewired the wires from the alternator to the regulator. Both the alternator and regulator are new. I am getting 12 volts at the output on the back of the alternator.
What else could I try?
Also, there is what looks like a ground wire on the hood of the truck that went to the firewall and is now cut. Would this have anything to do with it?
What else could I try?
Also, there is what looks like a ground wire on the hood of the truck that went to the firewall and is now cut. Would this have anything to do with it?
Moderator
Joined: Jan 2001
Posts: 56,980
Likes: 2,735
From: Virginia
Is your "I" terminal on the voltage regulator empty? If it is, you should have a red/green wire on the "S" terminal of the alternator. Make sure it's there, and make sure it has voltage when the key is turned to run.
Thread
Thread Starter
Forum
Replies
Last Post
jdwxly
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
13
Sep 23, 2019 09:52 PM
maytea
1973 - 1979 F-100 & Larger F-Series Trucks
5
Nov 26, 2017 06:23 PM
DIRTYSTEVEN
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
2
Feb 17, 2008 10:14 PM
Ratsmoker
1967 - 1972 F-100 & Larger F-Series Trucks
6
Oct 11, 2003 06:25 PM
