Power Problems

[wmnan]

Good day. I am having an issue with power. Where to start??
I have a 72 sii 304. It has points distro. Been having issues with rig starting and then shutting off after a short time. Battery was going dead so I got the 2 alts that I have tested both good. Lost all power inside the cab, so I took the daunting task of performing a continuity check on the entire interior wiring harness, some dirty conectors but all were good. Cleaned all connectors and re-installed. Turned the key and presto, it started, even ran for about half hour, shut it down cuz it was a long day. Next day went out it cranked real slow, then started. Took it down the driveway and it shut down. Turned the key and nothing. Played with the ig switch got it to start took it back up the house. Turn it off. Check for loos wires, found nothing. Tried to start it again, nothing. No power at all, no lights nutin.
Changed the ignition switch located on the column, no change.
Did a bunch of checks with the multimeter, noticed that the 1st 3 fuses have 12+volts with key off, as soon as I turn key on volt drops to 3ish on all 6 fuses.?? No clue where to go next?

 

[wmnan]

Wasn't sure how much I could write in one block.
I have a chilton repair guide, and have scoured the wireiring diagram relentlessly, I just can't figure out where my wires are crossed (no pun intended). I have checked all the fuses, all are good. If you need any photos please let me know what areas and how many. I live in ne pa and the snow has already started falling early this year, and I need the rig to plow snow when we get the big ones.
Thanks.

 

[FDChappie]

First disconnect the bulkhead connector on the passenger side firewall. Iirc you squeeze the sides and pull it out. Inspect it for burned and/or dirty connectors. If it looks good apply some silicone di-electric grease and reconnect. All the power from your alternator goes through this connector.

Then disconnect the ground cable from the lug on your battery and use a test light between ground and the battery lug with all accessories off. If the light comes on you have something on or shorted that is draining the battery.

 

[wmnan]

Hi fdchappie. Prior to this post there was one burned connector, a big blue one. I repaired it, and had the vehicle running after I did the continuity test on the interior harness. The other connections are a bit coroded, but what would make it just stop receiveing power? I did notice both connectors on the pas side are loose, is there a replacement connector available? I checked for power on the inside of the bulkhead connector, and have power to all the connections that have power from the outside. The battery check, can I use a multimeter to conduct this check, and how? I have just a basic understanding of how to use it. I am sure there is a short somewhere becasue the headlight switch has no power, and if I remember this switch should always have power? I was also reading in another post that there should be a jumper wire on the starter from the bat term to the "s" term. Why would that be? The wire diag shows nothing like that.
My rig does not have that jumper. Thanks.

 

[FDChappie]

While a multi-meter can be used to check for a short, they are usually limited to 10 amps. Exceeding that will result in a burned fuse. A test light is current limited by the bulb.

There no "easy" replacements that I'm aware of. When my alt wire burned, I just removed the contacts and ran a new wire all the through the firewall via the now open hole in the connector. If someone pulled the plug apart and broke the retainer tangs you're kind of stuck. Amphenol makes a great line of connectors, but they and the tool to put the new ends on the wires is expensive.

Your Scout perhaps has the "hot start fix" that uses a remote solenoid to crank the starter and that is the reason for the jumper.

 

[wmnan]

I understand the current thing, been there and done that whole blown fuse thing.
I took the bulkhead connectors apart again and did a further inspection, cleaned them as best I could, put them back together, rig started. So my next step is to replace the connectors. I am not going to take a chance of being 15 miles from home when it decides to quit on me.
There is a solenoid on the side wall, I thought it was just for the plow motor, but after a quick look lastnight it also has a power cable running to the starter.
I will pick up a test light just to be sure there is no unexpected drain on th battery.
Thanks for the help.

 

[Scoutboy74]

Sadly your chilton's manual is little better than a roll of toilet paper for dealing with most issues on your Scout. In all your posts thus far, I have not seen any mention regarding battery condition. The battery is your power source. This is where you should begin testing. The first thing to verify is that the battery is fully charged with a display of 12.x volts on your meter. If stored battery voltage is low, there is no sense in performing any further electrical tests until the charge has been replenished. If the battery displays a full charge at the terminals with the key off, but then drops significantly when you engage the starter, you should pull the battery to have it load tested for free at most any parts store/auto repair facility. It May have a weak or dead cell. Are your cables tight and corrosion free? Next junction in the stream is at the starter-mounted solenoid, unless someone has performed some sort of remote relay modification (quite common). Check condition of wires and terminations at this junction. Verify that there is no significant voltage drop from the battery at this junction. Next stop from there is the bulkhead connector. Connections must be rock solid and clean on both sides of the firewall. Next junction from there is at the back of the ammeter gauge. From there, the current path flows to the fuse block, ignition switch, and back through the bulkhead connector to the alternator.

 

[wmnan]

Scoutboy74,
I am tracking your thought process. I agree the manual is limited but it has helped me trace a few electrical issues.
I didn't mention the battery because I already had it load tested as well as a spare battery from a car I junked, both are running right around 12.35volts.
The confusing part to figure out was the flow of power.
I wish I could have found your explanation on the flow sooner, it would have made it a lot easier to find the problem.
At least now I know for the future.
I did find that the bulkhead connectors are a little on the corroded side. I just need to find an affordable way to fix it now.
My next issue is getting the rig to start and run consistient, but that will be another post after I get the connectors replaced.
Any recomendations????
Thanks again.

 

[Scoutboy74]

Sure, when the chitlons is all you have, it is better than nothing at all. I was in a hurry this morning and only glossed through your posts quickly to get the gist. One detail I missed earlier was the mention of the remote starter relay. Could you please post a pic of this item as well as as the starter solenoid? I want to see what wires are connected and how the terminations look. By your description, its possible that this conversion is not 100% correct or complete. The easiest way to check for a parasitic drain or short to ground is with an incandescent test light. You want to make sure that all vehicle systems are switched off, doors closed, lights off etc etc. Remove the negative battery cable from the terminal. Clip the alligator clip end of the test light to the dangling battery cable. Probe the neg battery terminal. If the test light comes on and remains illuminated even dimly, or if it pulsates off and on repeatedly, you have a drain/short. Remove one fuse from the fuse block and probe the battery terminal again. Did the light go out? You found the problem circuit. No change? Replace the fuse, remove another and repeat the probe test. Continue in this manner until the test light stays dark.

 

[wmnan]

Ok here are some pics.
I got one of the battery connections, solenoid, starter, and alt.
I will apoligize now, I screwed up. The cables are a bit twised coming off the solenoid and I mistakenly followed the wrong cable to the starter. So, as I orginally thought the solenoid only runs the plow.
Upon further inspection, as you will see, the battery has 2 power cables, one goes to the starter and the other to the solenoid.
From the solenoid, the 2 small wires run into the cab to the plow switch, the 2 large cables are the main feed and ground.
The rest you will have to tell me if it is correct.
Thanks

 

[wmnan]

The battery cables are a little unconventional.
The 2 smaller blue cables ground the motor, 1 large runs to the body, and the other to the plow. I also have a solar battery maintainer on it because it doesn't get used in the summer. Which I hope to change over the next year.
I didn't get a chance to check for any parasitic drains tonight, I will work on that tomorrow morning and let you know the outcome.

 

[Scoutboy74]

Yes, it definitely looks busy on top of the battery. More so than necessary I think. The primary negative battery cable should be no smaller than 4 gauge and it should terminate via a bolt threaded into the cylinder head. A short, 14 gauge ground wire can run from the negative cable and terminate through a nearby fender bolt. You could also run a copper ground strap from a bolt through the rear of the passenger side cylinder head to the body. That will take care of the engine bay chassis grounding. I'm surprised that the ground cable for your plow motor is not heavier gauge than what I see pictured. I think you'd be better served by using the remote relay to actuate your starter solenoid instead of your plow motor. I see that you have a wire connected to the 'r' terminal of your starter solenoid. Are you running a breaker points dizz or electronic right now? If electronic, you should remove that wire as it is only necessary if you have a points dizz. Now I'd like to see a pic of your coil that shows the wires connected to both terminals. I want to make sure you're not feeding the coil a resistive feed from the ignition switch if you have an electronic distributor. The resistive feed is necessary for breaker points.

 

[wmnan]

Ok. First off, there are no parasitic drians on the battery. I removed the maintanier and checked the negative side of bat as you described the light never came on. Just for shats I did the fuse panel and nothing.
Next, a simple swap of the neg bat cables should correct the ground issues. The 2 running to the motor are 12 gage. The one running to the cab is 4.
The neg for the plow is 6 gage.
I am running poins dizzy. Had them checkd for proper gap about 2 weeks ago.
Pic attached of dizzy and coil.

 

[carnuck]

Regulator is on the fender. If there is no ground wire from batt or motor to fender, alternator will not charge enough.

 

[wmnan]

The rugulator on the fender is for the plow only. The neg runs from the bat to the plow, thepos runs from the plow to the reg and then to the pos on the bat. That is how it's suppose to be right??

 

[FDChappie]

It looks like a po upgraded your alternator to a GM 10si alternator. It has an internal regulator so there will not be one on the firewall, or if it's still there it's not used. See if there is power to the 2 side terminals on the alt when the key is on. If there is the alt is bad.

 

[wmnan]

Ok, just checked real quick.
Blue wire by it's self has 12ish volts
the red wire from the starter has 12ish and
the the small green wire on the the left side of the plug is showing 3.6volts.
I had this alt tested at the auto store they told me is was good.
I guess that just means it's putting out 12volts :/

 

[Scoutboy74]

No battery drain is a good thing. Thanks for the pics. Let's try to keep the terminology clear to avoid confusion. The item being used to supply voltage to your plow motor is not a regulator, nor is it a solenoid. Its a relay. They are three different items that perform different tasks.
I'm thinking that a '72 Scout would have been originally equipped with a 10si alternator to begin with, but at any rate that certainly is what it has now.
The yellow wire with frayed cloth insulation connected to your coil + terminal appears to be the original resistor wire. As long as it hasn't been spliced, hacked or modified it should still be serviceable. I'd like you to take your multimeter and switch it to measure ohms in the smallest setting. Then disconnect that wire from the coil terminal. Switch the key to on and probe the ring terminal. We're looking for a reading of approximately 1.8 ohm. Post up with your result. Btw, this test is not related to your electrical power issue. This has to do with your engine performance issue.

 

[wmnan]

I will get that info for you tonight.
I have been keeping an eye on the battery the past couple days, it doesn't appear to loosing charge, I think the changes made thus far have corrected the drain. I do have a question regarding batteries. I have heard that it is common practice to run 2 batteries in series when using a plow to assisst in the additional power requirements. Would you recomend this and do the batteries have to have the same cca's? Or would it be better to just put a 140 or 160 amp alt on?

It looks like you burn the midnight oil often.
I appreciate your time greatly.

 

[Scoutboy74]

Two batteries in series would make 24 volts. I don't think that's what you want. I do recommend having an auxiliary battery that would be dedicated to the plow motor and connected to a switchable battery isolator. The isolator prevents the primary battery from being drained while the plow is in use. Before you even think about a high output alternator, you would need to completely gut your 40 year old hacked spaghetti wiring in favor of a new bumper to bumper harness. The factory wiring, even on its best day would not be able to handle the additional current output. I'm on the solid blue left coast, where we're so progressive we have to set the clocks back three hours just so we don't get too far ahead of everyone else. but sometimes I do make late pm and even early am posts. That's the life of a IHPA moderator. We're on call 24-7.