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Almost there I've been converting My 9/51 M38 back to the original 24 volt system it runs great just installed a new harness from Vintage wiring of maine. All the lights are working sooo close!

The battery gage ( Dis / charge ) # 7728854 is not working so I went to your gage trouble shooting down load and did what it said and I have 24vdc on #8 but nothing on #9 with switch off or on, running and not running. So I started looking for trouble shooting tips for the regulator and generator what i found there was going to be very difficult to do with only a volt/amp meter. The regulator is Delco Remy model 1118606 the generator is Prestolite mfr # GH-48401. I did have the generator tested(by a shop) before installing it and it tested good, I also opened the regulator and inspected it it was very very clean contacts looked to be almost new.

Please help, I live in a small town with out any real shops to take it to I'm a tech who work on a lot of dif elec components and have some skills but the is not my specailty.

Thanks Keith

The battery gage ( Dis / charge ) # 7728854 is not working

Do you mean the needle never moves off the zero position? What is the generating charging voltage at the batteries.

regulator is Delco Remy model 1118606

This is one of the correct service replacement regulators.

generator is Prestolite mfr # GH-48401

The correct generator is GHA4802UT. Recheck your part number/model number.

thats correct no movement from the neddle on the gage, when I get back home I will recheck the gen #, I also put my volmeter on + & - starting with 24.8 vdc I turned the lights on then crancked the motor with the switch off for a little now the meter reads 24.2 vdc turned swith on and cranked the motor, with it running and lights on the meter reading is still 24.2 vdc. so I don't think its changing.
It seems like it might be just something simple but can't put my finger on it. I checked all the connections.
Are both #8 & #9 supposed to have 24vdc when diconnected?

Thanks for helping
Keith

Looks like the amp meter is fine and your system is not generating. You should read, at the batteries, 27.5 to 28.2 Volts with the engine running above 1200 RPM. Since you just put it all together I must ask, Did you polarize the generator? If not then that may well be your problem. Unlike alternators the antique generator must know which way you want it's fields to be polarized before it will put out. Any time the generator is isolated from a DC power source for an extended bit of time it will lose the residual magnatism in it's filed magnets.

The long version by Dr. Vern is loaded on our downloads page at this link:
http://willysmjeeps.com/downloads/Gener ... zation.pdf

His version addresses both the "A" and "B" circuit systems but he does not address the sealed connections in out M series jeeps.

So to make it even simpler I'll tell you now you have a "B: system and it is polarized by momentarily applying battery voltage to the field of the generator. The easy way to do this is to removed that big cable at the plug on top of the generator. If you look very close at the receptacle on the generator you'll see that there are three pin sockets and they are labeled "A", "B", & "C". "A" & "C" cary the power load from the generator to the regulator. "B" is the field terminal. Connect a jumper from the battery cable terminal on the atrter switch to the "B" terminal in the receptacle on the generator. Do this for only a 1/10th of a second.

just got home and checked the gen # and it is GHA 4804UT I'm pretty sure ita a 4 next to UT not a 2.

thanks again
Keith

Yes I did polarize the generator following the instructions in your down loads. but i did it 2 weeks ago and have discnnected the bateries and reconnected them a few times. I will do it again.

Thanks
Keith

Am I supposed to get any voltage out of the reg on terminals A B or C? because I'm not getting any with the switch on or off.

Thanks Keith

I will be replacing my harness soon how easy is the one from Wiring of Maine did they supply DVD and did you need anything else other than tne harness

You need to be careful where you poke and pry with a probe that has an end grounded. The best way to piddle with the sealed 24 volt electrics is to buy a test adapter kit that gives you access to each circuit while the connectors are all connected.

#8 & #9 are connected to the amp meter's shunt down in the regulator. How much voltage you get on each depends on the amount of current flowing through the shunt and in which direction. You really need not piddle with those wires at all. The pins A, B, & C on the regulator are not that important either. A&C are the output from the generator and if theres nothing there you get nothing on the field terminal B with the plug disconnected. This is why you are not getting anywhere trying to test the beast with the connectors disconnected. The majority of test readings are always taken from an operating system with all connectors connected.

Once you establish that polarization is not your problem the next step is to "Full field" the generator to determine which unit is malfunctioning. When you full field the generator you disconnect the plug at the generator
and connect a volt meter to A or C and ground the volt meter to the farme. Now rig your jumper wire again as if you were going to polarize it. Before you make the last connection on the jumper start the engine and accelerate it to about 1500 RPM and tough the jumper to the battery cable terminal on the starter while watching the gage closely. She should jump right up to 28 to 32 volts. Only do this for a second or two. Just long enough to confirm wether it will put out at least 28 volts. If it does the problem is the regulator and if it doesn't the problem is usually the generator but could be the regulator.

All of this assumes all connections are clean and tight, all wires are installed correctly and the master switch functions correctly and has the wires connected correctly.

well I did something right, after repolarizing the generator it still was not charging. So i took the 3 prong cable off cleaned all connections, pulled the cover of of the regulator and cleaned all the contacts blew everything out reconnected everything , connected the battery and with the cover still off of the reg. played with each of the contacts WAOO the one farthest from the external connectors when you push that one down it made some sparks and stayed down until I pried it back up!!!!!! Well I figured I let the smoke out and all hope lost I Cranked it up with the volt meter connected to the batteries and ITS CHARGING yep now voltage is at 27.1 vdc great but still no ammeter I tried two other ammeters that I expected bad and nothing SOOO do I buy another ammeter and cross my finers??

Still need help But at least its charging
Thanks
Keith

You are quite lucky. Over the years we have had many occasion for someone to come on line and admit he forced a regulator contact closed and when the smoke cleared the regulator and the firewall harness was toast.

If you have a Delco 1118606 you have a large unit closest to the plugs which is the voltage regulator then the next unit going away from the plugs is the current regulator. Then you have two small units mounted 90 degrees to the current reglator on the far end of the assembly. The one on the data plate side of the frame is the cutout relay. This is the one you probably closed. This relay is open whenever the generator is not operating. Once the generator is turning this relay will close thus connecting the generator to the regulator. When this relay sticks open the generator will not charge but nothing gets hurt. When this relay sticks closed and the generator is not turning then this relay applies full battery power to the generator's armature leads A and C and the generator becomes an electric motor and will try to turn. One of two things will then happen. Either the belts will be loose enough for the generator to turn and it will turn until the batteries are dead or if the belts are tight enough that it cannot turn them the generator will overheat and burn up.

It is ok to check out the voltage regulator relays and contacts to ensure they are not stuck but IT MUST BE DONE WITH THE BATTERY GROUND LEAD DISCONNECTED TO PREVENT SERIOUS DAMAGE.



I would skip the amp meter. It only works with the old style mechanical regulators that have a shunt built in to them for it. If you later want to use the newer transistorized regulators you'll need to switch to a voltmeter so why not do it now. I prefer the voltmeter for several reasons. It is a better system health indicator, it uses a much simpler circuit and fits other applications. Instead of using wires #8 or #9 you splice it into the #27 instrument power harness (spider) or you can get the heavy truck spider that has a fifth lead.

You'll now have to see if the system is overcharging by running and driving it awhile.

Hello Weasel,

The VOM harness is really the only show in town right now. We are lucky in that he does a good job and supplies adequate written directions.

It comes with the main body, lighting, firewall and engine harness. He can tailermake add ins like turn signals for you as well.

It does not come with the generator to voltage regulator harness, radio harness, spark plug harness, or slave receptacle harness.

Weasel

The wiring harness is great, here are some things that slowed my install down.

1: once I realy got into the wiring after I received the harness and started installing it I realized that the instrement panel lights and the high beam indicator light did not have the wires with the connectors on them.

2: the high beam low beam switch didnot have the wire with its connector on it.

3: the horn switch did not have it two wires with connectors on it

4: be sure you have plenty of the single couplers and 6 of the 2 to 1 couplers

each of these were easy to fix after I had to reorder the parts and then I just sodered the connectors on I'm still waiting for my last order of parts.

good luck
Keith

Wes

It was the small 2 point contactor near the reg data plate. I removed it very quickly after it got stuck. I'm guessing why the system started charging is that the points had a thin layer of film over them from age so the slight cleaning i did to them allowed it to start working and after running it for a while and watching my voltmeter it seemed to be charging at 27vdc. I will keep But still my ammeter is not working!

I talked with john at midwest yesterday and thats what he suggested is to upgrade the regulator, gage and spiderharness. with it charging I have to think the gage is whats not working now? how likely is that if I get a nos ammeter from mid west or debella that it will be a working unit? because the one I have now appered to be nos it was in the original box and was in prestine shape with no evedence of it being used before!

comments and help is greatly appreciated

keith

Wes,
Couldn't the ammeter be tested by taking a 24volt light bulb, connect it in series with the ammeter and batteries and momentarily touch the connection to verify meter movement?