Ck weird electrical.

[k0ua]

Chris, there is a high beam and a low beam relay, one side of the coil of each relay is grounded, and the other side of the coil goes to the 1 and 2 terminals of the combination switch. This energizes the coil causing the relays to pull up making the contacts to provide high current 12 volts to go out to the respective high and low beam filaments of the headlamps. Notice that the relays are fed from a 20 amp fuse. I am sure there are some connectors in line with all of this. Do you have a volt meter, or even a 12 volt test lamp would suffice for this troubleshooting. You can pick up these at any auto-parts store if you don't have one.

James K0UA

 

[pickeringchris]

James, you've always been an awesome help on this forum, thank you...

Before I actually found those 3 connectors I unbolted the coolant overflow tank and moved it aside so I could get access to the relays. I unplugged them and did a visual inspection. They are all prestine with no water or corrosion in the connections. To be honest, where they are mounted it is impossible to get them wet via washing.
Both the low and high beam don't work although I do get a relay click for both. The 20 amp fuse is fine.

 

[pickeringchris]

This is a connector that goes to the head lights.

I am getting 3 volts across one terminal when the switch is on low beams. Nothing when switch is on high beams.

 

[pickeringchris]

Schematic.

 

[k0ua]

This is a connector that goes to the head lights.

I am getting 3 volts across one terminal when the switch is on low beams. Nothing when switch is on high beams.

Chris where do you reckon that connector is in relation to the combination switch and the relays? in other words, is that connector in the middle ? With the combination switch on one side and going out to the relays on the other?.. if so, I would suspect the combination switch.. How much trouble would it be to pull the combination switch out and inspect it for water and its connector ?. 3 volts of course is not right it should be 12 volts coming from the combination switch terminals going to the coils of the relays to energize them. So something is sure wrong with the 3 volt reading. You would normally measure with your voltmeter negative lead on a good clean ground and poke around with your positive red lead to take readings by the way. I would go directly to lets say the low beam relay coil and take a reading with the combination switch on low, and the key turned on and see if there is any voltage on the "high" side of the coil. the other side of the coil should be grounded to the chassis ground. If no voltage there, I would work backwards thru whatever connectors until I made it back to the combination switch. OR you could start at the combination switch. and measure for input voltage and out put voltages to ensure the switch is good. I wish I was there to help you.

 

[k0ua]

Look at the schematic while you read this..Notice on the combination switch, there is a B1 terminal. this is the control voltage feed to the combination switch and it has a 5 amp fuse going back to the "ON" terminal, which I assume comes off of the key switch.. we cant see where it goes as it "runs off of the map" so to speak. but anyway that is the feed. Then the combination switch terminals 1 and 2 feed the low beam and high beam relay coils respectively. The other side of the relay coils are chassis grounded.. When 12 volts is applied thru the combination switch contacts it should "pull up" the relay coils and make the armature (moving part of the relay) pull in and the contacts on the relay should then apply the standing 12 volts on one side of the contact to the other side thus closing the circuit and applying 12 volts to the filaments of the lamp. Notice on the relay the standing 12 volts comes thru the 20 amp fuse back to a terminal labeled "B+".. we cannot see where it goes, but I am betting it goes directly to the battery and not thru the key switch. Does this help give you some ideas how the circuit theory works? Now it is a matter of determining where the circuit goes wrong, and why. (pretty easy from where I sit ) not so easy in the field working on a tractor.

James K0UA

 

[pickeringchris]

That connector is after everything and just before the lights.... It is the connector you would unhook if you were to remove the hood.... I have 11.7 volts at battery and 3.0-3.2 across that connector (using a good ground)
I have to find the low and high beam relays... Apparently they are not the ones on the firewall behind the coolant overflow.... I can hear the clicking down below and inside where its very hard to see.
I have a full service manual but it doesnt show where anything is!!!! Doh!

 

[k0ua]

James, you've always been an awesome help on this forum, thank you...

Before I actually found those 3 connectors I unbolted the coolant overflow tank and moved it aside so I could get access to the relays. I unplugged them and did a visual inspection. They are all prestine with no water or corrosion in the connections. To be honest, where they are mounted it is impossible to get them wet via washing.
Both the low and high beam don't work although I do get a relay click for both. The 20 amp fuse is fine.

I went back and re-read what you posted... so you are saying that the relays both click "pull up" when they operate the combination switch.. then is there 12 volts on the moving contact of the relay? There should be 12 volts there all the time I suspect thru the 20 amp fuse. as according to the schematic it goes back to terminal "B+" which I suspect is battery voltage. So if the 12 volts is on the moving contact of each relay (look at the schematic) thru the 20 amp fuse, and you say it is good. then 12 volts should go out the non-moving contact of the relay heading to the filament of the lamps. Of course there will be connectors in line with this, and they could be faulty.. But it the relay clicks and pulls up, then the combination switch and the connectors from it have to be good.

James K0UA

 

[k0ua]

That connector is after everything and just before the lights.... It is the connector you would unhook if you were to remove the hood.... I have 11.7 volts at battery and 3.0-3.2 across that connector (using a good ground)
I have to find the low and high beam relays... Apparently they are not the ones on the firewall behind the coolant overflow.... I can hear the clicking down below and inside where its very hard to see.
I have a full service manual but it doesnt show where anything is!!!! Doh!

There should be a layout picture in front of the electrical section. showing the relative location of the relays.. at least there is on my DK manual.

 

[k0ua]

Like I said, it is a lot easier to "work on it on paper" than it is to actually work on the tractor with all the crap in the way. And not knowing exactly where things are located in the first place. Look at it this way.. you are going to be an "expert" when you get done.:thumbsup: