m38 12v converted wiring question

[futureuncertain]

Let me start by saying I know almost nothing about vehicle wiring. My m38 was converted to 12v before I purchased it. Since I bought the jeep it has been starting some times and not starting other times. When it's warmed up it runs perfectly. Battery is fine. When it decides not to run nothing happens.. no turning over or any other movement under the hood. Only the lights in the instrument panel go dim. I am able to push start it just fine, but that is getting tiring here in flat Texas. I feel that this is a simple wiring problem. I fiddled with the regulator once and got it to start, but that was a one time thing. The wiring is old (not military) and spliced a lot. I have looked around, but I am unable to find any simple wiring diagrams that would help me locate the problem. Did something come loose, fall off, or just quit working right? I have no clue how the system SHOULD be set up. Any help chasing down the problem would be great. Pointing me in the direction of a simplified 12v system diagram would be great. There is only a battery, starter, coil, regulator, alternator, and ignition switch, but I need to know how they are connected.
Thanks

[wesk]

You mention the dash lites dim and nothing happens. Also you mentioned this is intermittent. This is normally indicative of a loose or corroded connection. To properly inspect a connection you must take it apart. You should always keep a battery terminal cleaning brush and a brass utility wire brush handy. The first place to look is the two battery terminals. Remove both from the battery and clean the battery terminals, the cable fittings/clamps and then disconnect and clean both the opposite ends of the two cables. Hook it all up ans see what you get. There are a few places to check like the ground strap that belongs on the right front engine mount but I need to know what components your jeep has installed now.

Please post the Make/Model/Part numbers for the alternator (and regulator if external used), starter, distributor, horn, any other electrical components such as ignition switch, turn signal switch, senders, electric gages and etc.

[futureuncertain]

Messing with the battery is the first thing I did. The battery was new. I took out the old cables which looked really bad and replaced them with thick new ones. I just replaced the voltage regulator (Duralast vr715), and the alternator (delco remy Duralast dl7122). The starter is a delco remy 12v but the numbers on the plate have been rubbed off. I did not find any numbers/names on the other items. I do not have fuses on my jeep. I guess one day I will rewire the hole thing, but like I said I don't know anything about that and would love an idiot's guide for rewiring (from scratch) these things in 12volt.

I was running through the connections (again) and I found that the tab sticking out of the starter that the solenoid bolts to was loose/wet/rusty.
I cleaned that up a bit and tightened it up. When I turned the ignition the instrument lights are noticably brighter and it fired right up. I ran it, turned it off and it fired right up again. I don't want to get excited because I have done a few things that seemed to work for a while only to have it do the same thing. I guess if it keeps working then it must have been it.

[wesk]

That will cause your problem.

Your alternator must be a very early GM unit since you are using an external regulator with it. The DL7122 number is the Auto-zone PN for it nit the Delco Model / part number.

What I have always done over the years when I get a new used vehicle that has had the electrical system modified is to "Map the system". Since I can't see what you have it sure would make things easier if you post or email photos. Then I can ID your parts and draw up a working wiring diagram for you. I just went thru this with my Dodge M37 someone had partially converted to 12 volt and really buggered her wiring up.

Photos needed:

Overview photos of the engine compartment top view, front view and left and right view.

Overview photos of the dash from front and behind.

Overview photo of the front and rear of the jeep.

Battery installation: Overview and closeup of terminals and connections at each end of the cables.

Alternator: Front and rear view and any markings and terminals.

Starter: Overview and closeup of any markings and terminals.

Regulator: Overview and closeup of markings and terminals.

Distributor: Overview and closeup of markings and terminals.

Coil: Overview and closeup of terminals and markings.

Wiring: Overview of firewall wires and their routing. Overview of dash wiring and their routing. Overview of wires to grill for lights. Overview of wires to tail lights and trailer receptacle.

Turn signal switch closeup and flasher closeup.

Instrument cluster closeup of front of the entire set and rear of the entire set.

Light switch: Overview front/rear and closeup of terminals.

Master/Ignition switch: Overview front/rear and closeup of terminals.

Then some detailed info about parts.

Is your water temp, oil pressure and fuel quantity gage mechanical or electrical? If electrical is it the original 24 volt gage and sender or a civvy 12 volt setup.

Are you using the original 24 volt amp meter? Or has it been replaced with a voltmeter or 12 volt amp meter?

Is the horn and switch the original 24 volt system or a modified system?

I know this sounds like a lot but it is what is needed to set the wiring system straight, reliable and avoid a lot of smoke.

[xheadnut]

I has a similar problem, start one time not the next,everything looked good. I found out the ignition switch was bad if turned all the way it would not start, just back a little it starts everytime. Have new one to put in, but I'm thinking this might stop someone from stealing it, HA HA

[futureuncertain]

That would be great if you would draw up a diagram for me. I have to take care of a few things for work, but I think I can get to all (or most) of that stuff in the next day or so. Sounds like a lot of pictures. My problem is that I don't seem to be smart enough to post pictures to this site. ha. If you sent me an address I could email them.
Thanks for your time.