4x4 Not Engaging

411 Views 4 Replies 2 Participants Last post by itsmiillertime, 2 mo ago

itsmiillertime

Discussion Starter · 2 mo ago

Hey guys,

2005 750 Brute Force

When trying to engage the 4x4, nothing happens. I have read other forums and done all the checks that those mention and still cant find the issue. 2wd 4wd is NOT flashing. Below are the items that I have checked or did the fix on. When I unplug the actuator the 2wd 4wd light starts to flash. Connect it back, shut it down and restart it and its back to normal. Checking voltage at the 4x4 switch...with the key turned off, green wire shows 0 voltage. With the key turned on, green wire shows 1.7 volts. I realize this should be 4.5 volts. I have disconnected the connector that the 4x4 switch connects to and it looks good and the measurement is the same on the green wire. I dont know where to go from here. Are the relays in the rear part of this at all? The right relay gets warm after being turned on for some time. I swapped them and still have the same results.

Rear and front buss connectors - fixed (rear was bad and had a burnt connection)
Fuses in the fuse box are not blown - (two 10amp fuses and one 30amp and I pulled the fuse box out and checked the connectors/wiring housing into the fuse holder and this looks good)
Speed sensor has been changed and it does register on the screen
I have a spare actuator for the engine braking that I just connected up to the bike to rule out the actuator being bad. Same results. I assume they are the same other than the leads are different lengths and the 4x4 actuator has a different mechanism that sits inside the gear box to engage or disengage? There is not an oil senser on the front differential is there that would cause the system to provide inadequate voltage to essentially shut down the 4x4?

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NMKAWIERIDER

· #2 · 2 mo ago

Looks like you have check most everything. First, actuater control power is 4.4-4.7. With 1.7 volts there is clearly something wrong so check and clean all the pins on both the controler and the CDI. Some dielectric grease may have gotten in to them. Use a spray contact cleaner and look for one discolered. Second, you know it has to be moving between 2 and 12 MPH to work. Have you tried it moving? And lately, I assume you have had the actiator off but while off did you inspect the block and pin and that the coupler's movement is smooth and easy?

I can't help but think of the buss connectors as this was one of the symptoms of a bad one...but you say you fixed both of them. How about the ground that attaches to the radiator mounting frame?

The relays in the rear are just the interlocks so you can start it in neutral and in gear with the brake light on. The thing in the center is the roll-over sensor. If it starts, it's good.

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itsmiillertime

Discussion Starter · #3 · 2 mo ago

Right and that's what I had found in my research that I needed 4.4-4.7 volts on the green wire. Ok so I will use some contact cleaner on the actuator connector and the CDI (Box under the seat with three large connectors going into it) connectors. Right it has to be moving before it engages but I should still be getting the voltage just with the key on and without it being started correct? This is what has led me to believe that I have a wiring issue because until I get the voltage, its not going to engage because it cant!

I'm going to unwrap the rear buss connector and double check that all connectors have good contact. I took the grounding bolt out of the frame and it appears to be ok and have good contact but just for assurance, I will take it loose and ground it to the battery and see if voltage changes.

Good to know about the relays....I just wasn't sure and I to be honest, I am at the point where I don't know where else to look.

Thank you very much for replying to this and helping me out!! I will do the checks that I mentioned above and post a reply on what I find.

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NMKAWIERIDER

· #4 · 2 mo ago

Yeah when there is an error the control voltage is cut. I think its to zero but even 1 or so volts isn't enough to activate anything. If the 2/4wd light or the belt light is not flashing, the problem is outside the system...something not actuator or belt or control related. Again it's pointing to a bad connection somewhere. And you pulled the fuse box and check that connector under there...right? Tested the kill switch?

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itsmiillertime

Discussion Starter · #5 · 2 mo ago

So neither of those are flashing. I can get them to flash by disconnecting the 4x4 actuator or disconnecting the CDI with the key on. So I know the system is seeing the actuator/CDI. I agree with you on the connection thought.

So I just checked my buss fix on the rear and its good...all wires have contact with each other. Also, I checked ground and I get the same results by adding a lead from the battery negative to the ground bolt behind the fan. I did pull the fuse box, however, it doesn't look bad. And on the fuse box, the only fuse that will affect the 4x4 is the 30amp fuse correct? I believe that when I was checking this, only when I pulled the 30amp fuse did I lose my 1.7volts at the 4x4 switch. Maybe expand on the fuse box or would you like me to send a picture? From what I see, its just leads that have been landed into a plastic housing with spade connectors and then on top its made for the fuses to sit inside the spade connectors...if this is correct then yes these areas are fine...they were pretty clean honestly.

So the CDI has a buzzing sound when I turn the key on....is this normal? Could this be the issue? Can this be tested? I have access to an 05 650 and a 2020 750 if these are equipped with a CDI that can be swapped out for testing purposes.

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