Totally stumped w/ charging sys. issue

[newmaac]

Trying to help my son with his 69 C 10 and it's charging issues.
I'll try to keep this brief, but it might not work that way.

We installed a new alternator, (bench tested positive, @ 14.6 volts)
New regulator.

Charging nothing!
The voltage at the battery is about 11, whith the engine running or not.
When the battery is disconnected with the engine running, engine dies immediately.
Voltage @ the red & black terminals on the alt matches what is currently stored in the battery.
All connectors look fine.
The fusable link on the positive from the battery has been eliminated by a PO.
We unwrapped the wire harness and all wires look fine.

I was told that in SOME alternators, there needs to be a small current going INTO the alternator, in order to create the output FROM the alternator. If so, which wire is supposed to bring current to the alt?
Can anyone tell me if we should have current @ the blue or yellow terminals on the alt, before starting the engine? If so, how much?

Any suggestions would be greatly appreciated.
Thanks in advance

Mike, (who hates electrical gremlins)

[my67c20]

Did this problem just show up? Has he had charging issues in the past? How was the truck running before this happened? Any photos? Best thing to do would be to search the forum for a wiring diagram. Verify all the connections are correct. If so check each wire for continuity. Sometimes these old dryed out wires crack. If still unable to solve the problem i would chase down an HEI and make the change to the internally regulated alternator and ditch the regulator. Be patient this community will help. Oh and welcome.

[newmaac]

Good questions.
This is a project that we bought without a motor and trans.
To the best of my knowledge, it has never charged since the new motor installation.
The distributor has been upgraded to the HEI, but the alt is still an externally regulated one.

[old Chevy guy]

Dont assume the regulater is good just because its new. Its been a long time since I fooled with a regulater and feel free to wait for someone with more current(no pun intended) experience chimes in but if memery serves the way we used to check regulaters was that if you jumped the yellow and blue at the regulater with a jumper or paper clip and the truck charges,stays running when the battery is diconected the regulater is bad. I would check the wires yellow and blue for continuity like my67c20 sugested first though. If you have the same as battery voltage at the red wire at the alt then that wire is good. I dont remember there being a black wire on any of my truck alternaters,is it a ground? Also the battery should be 12 volts is your meter ok?

[cdowns]

have you had the battery fully charged on a battery charger and checked to see if it capable of holding a charge
do you have the regulator ground wire hooked to a good grounding spot

[VetteVet]

Here is your charging diagram. You need 12 volts on the brown wire on terminal
4 of the regulator with the key on and 12 volts on the no/3 terminal at all times.
You should also see 12 volts on the R terminal at the alternator and 12 volts at the large stud on the alternator. Like Cdowns said make sure the regulator is grounded and the alternator and regulator are grounded together.

[krazy_texan]

how is your chassis ground from your engine block itself, i honestly think it sounds like a grounding issue cause bad or no grounds can really screw with your head and do some wierd crap they are really unpredictable

[VetteVet]

Here's a better look.



This is how it looks from the inside of the cab. BTW do you have the gauge dash or the idiot light dash?

[newmaac]

Thanks folks for the replies. We will double check the grounds tomorrow, then test the current on the various points, per Vettevet's diagram.
I will post my "success" results soon. ( I hope)

Mike

[ChevLoRay]

Per "Click and Clack", if you think that there is a grounding issue, take a jumper cable and connect it to the block of the engine and to the negative post of the battery. Take the other one and connect it to the engine and to the chassis. If it works well, then you'll know you have a ground issue.

How about the engine and lighting harnesses. If they're original, it would be a good time to replace them with new stuff. www.wiringharness.com has harnesses in OEM configurations as well as those that it modifies for HEI and 1-wire alternator systems. I can vouch for their quality and also tell you that they're helpful on tech issues.

[stsalvage]

Ya this site can fix anything But.I'm not one to modify anything. I feel if you PO took out all the fuse able links time to buy a new engine harness and light harness spend the 250.00 and have a better truck with No cut wires

One last thing wires only last 30 years in any condition.Its like tires rubber dyes out and cracks.I like having a good peace of mind that everything under the hood is working Get the wire harness for the HEI

WWW.TRUCKANDCARSHOP.com

trust me the guys from M&H wire harness they make a complete copy of your factory harness and it comes with the wire gutters and all the factory connector

Here is one from my 1968 chevy truck I showed a few other pictures of the harness and regulator and how its hooked up and the fuse able link

[newmaac]

14.4 VOLTS, BABY!!!!

The brown wire going from the regulator to the dash was damaged.
Ironically, when we looked at this truck prior to purchasing it, one of the things that appealed to me was the condition of the original wiring. It is as "unmolested" as one would hope for, considering it's age.
That being said, the "damage" to the brown wire was from some knucklehead splicing into it for a switched power source. DOH!!!

Thanks for the help folks

Mike

[chevytruckluver]

Good to see you found the problem!
The guys here usually know what they are talking about.