Keith Roberts

I took the truck to a mechanic because a bad switch. He by-passed the ammeter on the cluster. he connected the main red wire to the black wire which goes to that welded splice, one of those go to the light switch, the fuse box,the switch itself and to the alternator. Is the wire going to the alternator right??? because i seen an article, it was talking about bypassing the ammeter. it showed the bat post on the alternator to go straight to the starter relay...not the welded splice. but the wire from the welded splice showed to connect it to the main fusable link( the red main wire) so i thought that would fix my problems, and it didnt. It idles about 14.3 to 14.8. When you give it throttle it will jump from 15.5 to 16.0... the when it idles back down sometimes it hesitates then shuts off or still idles. so i followed that diagram online...from the alt to the relay, it showed to use a 14guage fusable link between the relay and wire coming from the alt. i did that and put a 20 blade fuse...it blew it as soon as it fired up....so i tried a 30 fuse,,,blew it to. so i now got the black alt wire spliced to the 14g fusable wire( no fuse, just the wire). it idles fine. Any help??

RacerHog

You have a bad Voltage Regulator to start with.... When you replace that... Make sure it is grounded well...

Just an FYI or food to think about......
You used a 30 AMP fuse.... And a Alternator that puts out 65-85 AMP's on the circuit... Yes.. it blew the fuse...

Keith Roberts

i have replaced the regulator, ballast, igniton control M. alt battery

RacerHog

Lots of equipment is not going to like 16+ volts..

I would try another voltage regulator and. I like to run a extra wire from the regulator to a engine bolt just for good measure... Try a good 10ga. Wire.
Some of these cars/truck start loosing there connection grounds threw out the body and chassis and folks often over look them...
You know... Engine to body... Body to frame... Frame to Bed... Electrical....

Once you by-passed the AMP gauge... Most all your electrical should have began to work again.. Youll be able to build on it from there...

Just my 2 cent

RacerHog

Have you tested it for a short?....
That might be causing a bigger load draw?

DDodger

HERE IS what you must test for

The Voltage Regulator (VR) MUST see "as close to" battery voltage as possible. In other words, whatever the battery is "doing," the VR MUST see that.

The VR MUST be grounded to "same as battery" MUST

The VR IGN terminal is also the voltage SENSE terminal

There are 4 areas of might be trouble

1.....Battery might have problems......rare but might

2.....VR might be malfunctioning, also fairly rare, because if they regulate at all they are usually OK

3.....VR ground. This does not happen all that often but is more likely than 1 or 2

4.....VR voltage supply. THIS IS THE most likely. What I'm referring to is VOLTAGE DROPS due to bad connections in the circuit path from the battery to the VR IGN terminal.

In some vehicles, there are MANY points this drop can occur, and a little bit of drop can happen in ALL of these points, which adds up. THE TOTAL DROP causes battery charging voltage to RISE by the amount of the voltage drop!!!!

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How to fix?

1....Test the ground. With the engine warmed (the VR is temp compensated) and the battery charged, run the engine at a fast idle to simulate "low to medium" cruise RPM. Make this test first with all accessories off, and then again with lights, heater, etc all turned on

Set your multimeter to LOW DC volts. Stab one probe into the top of the NEG battery post. The actual battery POST. Stab the remaining post into the mounting flange of the VR. Be sure to stab through paint, chrome, or rust.

What you are hoping for a very very low reading, the lower the better, and zero is perfect. More than a couple of tenths (.2) volts is too much

Even if the VR ground reads OK, it is a good plan to unmount the VR, scrape the bolt holes clean on the firewall and VR and remount using star lock washers.

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Next, check the overall harness drop. There are two ways to do this

First get a point as close as possible, electrically, to the VR ign terminal. The "high" side (key switch connection) to the ballast resistor is the best. Others are the blue alternator field wire, and a wire that is switched "ignition run" under the hood, such as electric choke if used

1....First method. As in the ground test, run the engine at fast idle. Hook one meter probe to the "ignition run" point mentioned above. Connect the remaining probe to the battery POS post. Once again, you are hoping for a very very low reading, the lower the better. More than .3V you should look into the problem

2....Second method. Monitor the "ignition run" wire you hooked to above, to battery NEG. Again run the engine. NOTE that reading.

Now monitor across the battery posts and note that reading. If you performed test 1, that reading should be the same as the DIFFERENCE between these two readings in test two

EXAMPLE:

The battery, when charging, running in test two shows 16V

The IGN "run" wire to ground shows 14V. Difference is 2V.

You perform test 1, and the reading is 2V!!!!

What this means, is that the connections, terminals (and switch) in the circuit path from the battery to the VR has a PROBLEM

"Most likely" (original wiring)

Fuse link going through bulkhead (that bulkhead terminal)------------ammeter terminals and or the AMMETER ITSELF............WELDED SPLICE (rare but has happened).............the IGNITION SWITCH CONNECTOR............THE SWITCH ITSELF.............BACK OUT THE SWITCH CONNECTOR (on ignition run wire)...........BACK THROUGH the bulkhead on the ign run wire...........and on some engines, some years, there is a separator connector under the hood which drops loose most/ all of the engine harness. In the A bodies this is the ONLY white connector under the hood.

IF YOU don't want to rewire the entire vehicle, and everything else seems to work, consider adding a relay. Find the "ign run" wire which comes out of the bulkhead and runs TO the ballast resistor. Cut that, and run the wire out of the bulkhead to the coil of a Bosch style relay. Run the remaining end to the contacts, and run a 20A fuse/ breaker from the remaining contact to the starter relay. This will now provide "solid" battery voltage to the under hood loads

Keith Roberts

the wire from switch to ballast, that ballast prong only shows 2 less volts than the other prongs on the ballast. the other wire on that same prong goes to POS post on the coil. Also the ballast gets real hot

Keith Roberts

i done the first test. Touched ends on NEG post and VR flange. it started at like .1 .2 .0 but then it started jumping a lot higher. like up to 8.5 volts

DDodger

First, remove the VR, scrape the mounting clean, and remount with star lock washers. Check the engine to body grounds, or better yet, add better one(s) One way to do this.......look at the passenger side head where the alternator mounts. THESE same bolt holes are on the driver side head on the rear. Get a short bolt and a short "starter" cable (eye to eye) and bolt to the head, and a good solid point on the firewall. the master mounting bracket is a good place.