'73 JDX4 wiring problems

[ejazz]

I have a '73 JDX4 and I am having some lighting issues. My sled originaly was electric start but the starter is gone. My problem is that I keep blowing the headlight, tail light and dash light. Thinking it was the voltage regulator I purchased one off of EBAY. I didn't get the one that was pictured when I bought it. My original had a brown and yellow wire coming out of it. The brown went to the chassis and yellow spade plugged into a brown wire. The one I purchased has two yellow wires coming out of it and I don't know which one should be the ground.

Also, is this system a type of positive ground? I have a battery in it and does the negative then go to the solenoid and the positive to the chassis? There is also three black wires hanging near the battery. They come from under the dash and are plugged into a pigtail. The backside of the pigtail has a red, green, and yellow wire going to it. I can not find these wires on the schematic. Are these black wire supposed to be grounds that are just hanging there. Thanks for the help.

[harleysportster]

The new regulator you bought with the 2 yellow wires, shouldn't matter which wire is grounded. The lighting system is AC voltage and the starting system is DC. The conversion from AC to DC voltage occurs in the rectifier to charge the battery. Here is a wiring diagram of your sled.
http://www.jdsleds.com/tech/wiring/73wiring.jpg

[ejazz]

I guess I don't understand AC voltage in the lighting system. There is one wire going to the voltage regulator with the juice. Does the regulator "ground" out a percentage of the volts to the chassis so the lights don't blow. If I am checking the power through the wire to the regulator, should I be using the AC setting on my multimeter and if so, what should I read? Does the battery does hook up normally then, ground to the chassis? Thanks for your help.

[JDFanPa]

It is easier to just use a test light to check the yellow wire for power and the regulator controls the voltage so it doesnt pop the lights. The battery hooks up normal like in a car but if theres no starter theres no need for a battery the lighting coil on the engine provides the juice for the lights.

[ejazz]

No wonder the '73 wiring diagram doesn't match! The sled is a '74! The registration card says '73 and the tunnel says June of '73. I just assumed it was a '73.

[ejazz]

Harley says that the lighting system is AC. What should the reading at the headlight plug be if I have the new voltage regulator hooked up right? Should it be read in AC or DC. I do not want to put another headlight in and blow it.
Or is it that the alternator is putting out AC and the rectifier changes it do DC to run everything?

[JDT]

ejazz----First off your diagnosis of a bad voltage regulator is more than likely correct.

Not knowing what brand and type of regulator you have now I would recommend that you test it with your ohm meter before you hook it up. Some are internaly grounded to one of the wires and others are not.
Test from either wire to the case of the regulator. If one wire has zero ohms to the metal mounting part of the unit than that wire has to be grounded. If neither one is zero ohms that it does not mater which yellow you attach to ground.

While you are at it test between both yellow wires with the ohm meter. Infinity or open means the regulator is junk. Zero ohms means the regulator is shorted and junk.
A typical resistance reading is 100 to 200 ohms. A voltage regulator is nothing more than a resistor. Some regulators only have one wire and complete the circuit to chassis ground through the case or heat sink.

Regulators build up heat and must have way to dissipate that heat away. That is why they need to be mounted to the chassis or frame. A two wire regulator would work for a while just hanging there or mounted to plastic but as the heat built up it would cook itself to death and then go open at which time all the bulbs in the system would burn out.

The electric start system's battery is negative ground. But as JDfan stated, if you do not have a starter on your sled than you do not need a battery. Remove it as it's only function was to close the solenoid and crank the starter motor.

Likewise if anyone has a battery in their sled and they are not using the electric starter for any reason and always pull starting the machine it would be advisable to remove the battery. A dead battery can freeze and that will crack the plastic case. Even though the battery may not have had enough juice to crank the engine over the acid in the battery can still eat a hole in the battery box and the bellypan.

As for the three wires you have hanging there....
Black is typically ground on JD's.
Yellow is hot for the lights.
Green... there are no green wires shown on the wiring diagram. Check the color again. If it is in fact green than someone may have made some changes from the factory wiring. You will have to check the diagram very closely to see where it goes and what it is for.
Is the multi-wire connector with 10 wires on it still on the sled? This would have been originaly attached to the frame in front of the recoil with a black zip-tie.

From what you have discribed so far it sounds like the wiring has been changed.


Testing the lighting system with your meter you need to have it set for AC. At idle you may read somewhere between 7 and 11 volts AC. As the rpm increases the voltage will go higher but should never go above 14.2 volts or you will start toasting bulbs.
NEVER unhook the voltage regulator with the engine running. If you do all the lights will get very bright and then burn out. Without the regulator in the system the voltage can be anywhere from 15-24 volts ac.


You asked about the rectifer on your sled. It's only function is to convert the AC from the sleds electrial system to DC to charge the battery.

When the sled is running you should read the same voltage at the headlight connector as you do at the regulator.... or at the taillight for that mater.

The alternator you refer to is better discribed as a magnito and it produces the AC voltage when the engine is running. It also produces voltage when the engine is turning like when you are pulling the recoil over. The lights will glow dimly as you pull the rope even with the key off as the lighting system and the ignition system are not interconnected.

I know this was long winded but that I figured it would make more sence this way.
Hope you get it straightened out.
Good luck,

Todd

[harleysportster]

Here is the 74 wiring diagram.
http://www.jdsleds.com/tech/wiring/74wiring.jpg

[ejazz]

Thanks Todd. Awesome explanation. That is what I needed. There is a dark green wire in the system. The plug had a green, red and yellow wire going to it. What I didn't see though was that the previous owner had cut the three black wires coming from the dimmer switch. The plug was hanging there with the three black wires hanging out of it and they were twisted together. This still allowed the headlight to work but of course not the dimmer. I spliced them back together and now have power to the headlight plug the correct way.

The other plug hanging there is for the tach which I do not have on my sled.

I put BR8ES plugs in so that I can use my meter near the machine. It is amazing the electrical field that is put out from the engine. Thanks again guys for your help. I am going to go and try ohming my new voltage reg and will let you know. Thanks again.

[ejazz]

I set my meter to 200K on the ohms.

Yellow to yellow= 165.5 ohms

yellow #1 to case = 00.0 ohms

yellow #2 to case = 116.5 ohms

[JDT]

If the dimmer switch on your Deere has three bleck wires on it than it is aftermaket or from a different brand of sled. Not to worry, as long as the switch fits in the grip it you can change the connector end as needed to mate up with Deere's connector. Many other brands in this era used the same switch but different color wire or connector positions.

Please note that wiring it up the headlight as the previous owner had done caused both the high and low beams to light up at the same time. While this almost doubled the light output from the headlight, it put a huge drain on the lighting coil. The light has 60W high and 55 low and together that is 115Watts. The lighting coil is rated at 120 watts. Add the 8 watts for the tail light and you have exceeded the limit of the coil. Apply the brake and that lamp adds 26W and now you can fry out the coil.

To address the nosie you found... the plug wires that were originally on the sled are solid core and obviouosly still are. And the OEM plugs were non-resistor which both contributed to a high level of egress. Newer sleds have addressed this and have very low levels of RFI.

And your regulator yellow wire #1 is the one you need to hook to ground. Hooking that wire to the yellow wire in the machines harness would put a direct short to ground on the lighting coil and surely smoke it due to a very high amp draw.

It is common to find wiring modifications on old sleds as there was always some guy out there that thought he knew more that the factory engineers or simply thought he knew anything. I feel it is always best to check over the wiring on a machine after you aquire it and look for potential problems. Non-original connectors and splices are the first thing to check. But also check wires and harness near moving parts or the exhaust system. Also don't forget to check hidden areas when wires run under things like seats and gas tanks where they can get squished and the insulation rubbed through.


Todd

[ejazz]

Todd,
Even after I hooked the regulator up, I still get 23 AC volts at any of the light plugs idling. Revved up it is near 60 AC volts. I cleaned all the grounds thinking maybe it was not grounding to the chassis but with the same results.

Where the ten wire plug meets the plug from the battery box, there are two black wires that are not connected to anything. It looks like the plug from the engine side will accept another plug connecting the two blacks to possibly a ground?

I wish I had my camera here to shoot you a picture. The only other plug that is not hooked up to anything looks like the plug for the tach with a brown, brown/white, and yellow. This brown wire is also where the voltage regulator plugs into just like on the wiring diagram.

The regulator I bought is Item number: 110133951678 on EBAY except the one he shipped me yas two yellow wires coming out of it.
-Eric

[harleysportster]

Eric, if you see this by 4:45 ET, go to the chat room

[JDT]

Eric, check the ground connection on the regulator. You may have to scrape off some paint on the frame to ensure a good conection where it bolts down.

With your OHM meter check between the engine case and the frame of the sled. This should read zero ohms or very close to zero.
I bet you will find that it is open.
If you not already done so unplug the connector near the battery that has ten wires on it.

Look at the wiring diagram that harley provided the link to.
You will notice that the drawing shows two jumper wires between the connectors. These must be in place if you are not using the electric start. One of these jumpers is the ground interconnect for chassis and engine case.

Is that the two black wires you said were not connected to anything?

Without the tie betwen engine and frame the regulator is not going to do anything as it is on an open curcuit..

Let me know,
Todd

[ejazz]

Thanks Todd. Yeah the jumpers were not in there. But, all the messing around and I lost all juice from the lighting coil. Any body have any used parts?