Topic: Electrical Gurus Question?

[bryancobb]

Well I got all of my NOS Ford Harnesses in, in preparation to set in the engine.
I put a new repro concours solenoid, and Voltage Regulator.  Neither the
alternator harness nor the backup/neutral switch harness were plugged up
because they're on the engine/xmsn.

I wanted to test all systems that I could, while the engine was out so it would be easier
to get access for troubleshooting.

I sat the battery in and hooked it up.  I turned the key to ON.  All lights, horn, A/C blower,
Heater blower, and everything else worked fine.

Then I turned the key to ACC and started checking everything again.  I noticed light smoke
beginning to come out of the AMK voltage regulator so I ran and got a wrench and took off a
battery cable.  It took me about 20 seconds to get it off and the voltage regulator only had
minor smoke. 

What did I do?  Does the alternator have diodes or other components that keep this from happening?

[midlife]

You have a short somewhere in your ACC/RUN electrical lines that is not fused.  Here's the best way I've found to hook up harnesses and find shorts before applying power:

 First, always install electrical wiring with the battery disconnected.
Physically install the underdash harness with fuses.  Connect all underhood and taillight harnesses.  When ready to check out the harness, close all doors, turn off all lights, accessories, etc.  Then use a digital volt meter to measure the current draw across the battery.  Make sure both battery connectors are disconnected.  Connect the positive battery cable to the starter solenoid.  Leave the negative terminal disconnected from the battery.  Place one probe of the DVM on the negative battery cable terminal, and the other probe on the negative battery post.  Be sure that the DVM is set to amps, DC.  If there are no shorts in the wiring connections, the reading should be on the order of 30 milliamps or less.  Anything above 1 amp indicates some accessory is on; readings above 10 amps (may blow the fuse on the DVM) indicates a dead short.
 If you have a short, disconnect all other wiring from the starter solenoid post where the battery connects and re-measure the current.  If current drops, the source is the underdash wiring harness or the harness from the starter solenoid to the firewall.  Reconnect the wiring to the starter post and then disconnect the underhood harness from the firewall and test again to isolate the source of the short. 
If the short is not in the underhood or underdash harness, the problem lies in the alternator or voltage regulator.  Disconnect each of these in turn to isolate the source.
 If the short is evident and you see high current, keep the battery negative side disconnected and remove one fuse at a time.  Measure the current as above.  If you now see low current, there is either a short or an item on that particular fuse circuit is on.  Turn off that item and continue checking.
 Eventually, you’ll have low current readings with all fuses installed and all wiring connected.  At that time, and only at that time, is it safe to connect the negative battery cable to the battery.
 

[bryancobb]

Good methodical system you describe.
I just plugged all the brand new harnesses up like the Osborne manuals and the schematics show, and expected it to work.

I don't really see where a short could be other than internal to the voltage regulator.

[midlife]

You'd be surprised how many places shorts can occur.  A pinched wire somewhere; a dash cluster ammeter shorting to the case; a door jamb switch shorting to the door post (65-68); a 66 fog lamp power connector (a ring connector not fused!) contacting the chassis; the list goes on and on.  For some reason, a lot of NSS wiring is burned up, presumably pinched somewhere near the transmission. 

[bryancobb]

I think these VR's are the old vibrating points type.
If I turned the ignition switch to start , to hear the solenoid if it was working...
...could I have welded a set of the VR points together creating as short

[e093116]

I had the same thing happen once a couple of years ago on a new AMK VR.

VR continued to work fine, I concluded that there was some oil or grease on the components that got hot and burned off, because it never created smoke after the initial power on.

Does your VR still work?  Maybe you don't really have a problem...

[bryancobb]

I am inclined to agree with you.  I cannot tell if it works yet because the engine is not in.  I have a new $300 DeadNuts alternator and I'm just afraid that if my VR has a problem, it may fry my alternator.  I may get a new VR just to eliminate that worry.