Hey all, my name is John and I have a 1974 W100 with some issues. I have replaced the alternator, voltage regulator, battery, and went through all the wires associated with the charging circuit and cannot find anything wrong to the death of me. This has been killing me and I would really like some help in possibly understanding. I replaced the alternator 2x, voltage regulator 3x, battery 2x and now I am seeing the ammeter go to a high charge but pulse when I drive down the road. I am to the point of just giving up but would like to get this fixed before to long. Can someone give me some ideas please as to what to do....

 

Welcome to DF

Hi John
I'm going to move your post to the Ram Van section, The members are very knowledgeable and may have some ideals.

 

Why? He has a W-series pick-up and this is the B-series van forum.

 

Hello John, have you checked to make sure all your engine bay grounds are properly connected?

 

Yes I did, also did a continuity check through all the lines associated with the charging system and found nothing wrong. I am wondering if the ammeter might have something to do with it or if there is anything under/behind the dash that would cause this to happen. The new alternator I put on along with the voltage regulator are showing a solid charge at 12 volts, so I checked the alternator by doing a field test and shows that the alternator is not at fault, but still at a stand still as to why the regulator would stop it from sending a charge. This is getting old really fast, and I hope that someone can give me some idea as to where to look. Thanks

 

Hello. Just a question - shouldn't it be 13.5-14.2V?

 

Yes you're correct, it should be that high in order to properly charge the battery.

 

Yes, your both correct, unfortunately it is declining as far as where I first posted itwas staying at a steady 12 volts. Checked it today and it registered at a 11.5 which is starting to confuse me. I disconnected the ammeter and tied the wires together thinking it would show the the ammeter was at fault and still nothing. So if I no one has any ideas where to look for a possible cause I will just have to tear everything apart and start over from scratch.

 

Follow the (+) cable from the alternator to the battery.

At some point along that path there will be a fusible link, a length of wire with a different type of insulation.

When they blow, they are supposed to look burnt and stretch out.

Many times when they get this old they do not blow in the prescribed method, and can be intermittent at times. It might even test properly, but the second it sees any current it opens up and decides to pass no current.


Recharge your battery via a battery charger asap unless you like replacing batteries. Never rely on the alternator to fully charge a depleted battery, they do a very poor job bringing it above 80% unless you are doing some interstate distance driving.

 

You know, I went and bought a book because maybe I was missing something in the wiring diagram and was looking around for a fusible link, I cant find one anywhere. Would this be under the dash or in the engine compartment. I even took all the wires out of the tape that it was all wrapped in and couldn't find a thing. It just seems that I have a real problem on my hands.