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Pedro Goncalves
Pedro Goncalves,
Category: Classic Car
Satisfied Customers: 13
Experience:  Licensed Master/Hybrid Technician at Mendes Motors
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Just acquired 1981 VW Rabbit diesel pickup that has

Customer Question

Just acquired 1981 VW Rabbit diesel pickup that has alternator light on. checked volts at battery, engine of and running, nothing from alternator. bought rebuilt alt.= same thing, no change. have voltage to alt. from D+ exciter wire and cleaned all connectyions and added grounds. where do i look next?
Submitted: 6 months ago.
Category: Classic Car
Expert:  Pedro Goncalves replied 6 months ago.
A couple of things come to mind. Even though you have voltage doesn't mean the actual wire is good. As you probably already know. The wires are multi copper wires. They can be broken an only one or two wires giving you the voltage. So, basically it gives you voltage but not enough amperages to make to work. Please, check the wires. Another thing that can happen but it's very rare. The new alternator could be defective. It has happened to be before, me chasing my tail because I just replaced the part with a new one so I was ruling it out. So, see if you can get them to replace that one. I hope I helped.
Expert:  Pedro Goncalves replied 6 months ago.
Another thing. Are you measuring the voltage on the rear of the connector? If so you might need to tighten the terminals in the connectors. When probing always use a thin prob so it doesn't widen the terminals. If you liked my answers you know what to do. :-)
Customer: replied 6 months ago.
I thought that it may have been the "new" alternator already and took it back and had it tested yesterday and it checked out good. The exciter wire has a spade connector that is soldered so it cannot be tightened. The other 2 heavier wires from the alternator tie into the battery wire and then continue thru the firewall to the inside of the truck, do you know where these go as this is the only thing i have not really checked. thought i would ask before tearing the inside apart as it is small and cramped and i am not exactly ennano. gracias!
Expert:  Pedro Goncalves replied 6 months ago.
Okay. Perfect. So we know for sure that the alternator is good. So there's no doubt that there's something wrong with the wiring. Please, confirm the condition of the wires. Please keep in mind that checking the resistance will NOT give you a valid answer. Because as long as one copper wire inside the wire is touching you'll always get close to zero resistance. (ohms)
Expert:  Pedro Goncalves replied 6 months ago.
Yesterday, I encountered a problem with a terminal that I had current up to the end of the copper and the terminal wasn't allowing any voltage to go thru. I was blown away. I had to replace the terminal and resoldered. I hope I helped

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