Yamaha Grizzly ATV Forum banner

4WD Servo Problem

1 reading
13K views 15 replies 8 participants last post by  Walley_eye  
#1 ·
Lots of posts on solving the 4WD/2WD issue, but I need a little help yet.

My 2007 700 Griz is not letting me switch between 2WD / 3WD / 4WD.

I verified the fuses were okay.

I exchanged the selector switch on the right handle bar with my 03 660 Griz (exactly the same).

I removed the servo from the front and inspected the slide and gear inside the differential. All seemed okay.

I opened the servo unit and looked inside. Clean grease and no water traces. Gears seemed okay.

I jumpered the the number one and two electrical connectors with 2 C cell batteries taped together in series and operated the motor both directions.

The dash display icon indicates it's in 4WD whether I have the servo plugged in or not and the selector switch is in 2WD. I confirmed the differential is in 2WD because I can spin the front wheels independently of all of the other wheels when on a lift.

My next step will be to test the relays but I'm having trouble locating them. I believe they are under the front plastic and are inline wire connections, but the wire colors don't match the service manual. Help here is appreciated.

Jeff
 
#2 ·
On the 660, they are under the seat on the (top of) the plastics but, on the 700, they are under the "hood" plastic in the same plastic "tray" that holds your battery. Refer to this parts diagram...they are #39, #40, & #42. They are little plastic boxes about an 1.5" tall.
 
#3 ·
Yea and in the yamaha service manual they are switches #1,3,4 on page 9-1
#1 is 4 wheeldrive motor relay #3
#3 is 4 wheeldrive motor relay #2
#4 is 4 wheeldrive motor relay #1
like dizgrizz mention they are in tray at battery compartment.
 
#4 ·
Looks like the fuses are on the left side and some relays on the right. But I thought the relays on the right were not for the 4WD. I then saw a bundle of small boxes on a wire harness. There were three square boxes and two rectangle boxes bundled together. So I thought those were them. However, the wire colors were not consistent with the service manual.

Probably time to start pulling things out of the way to get a better view.
 
#5 ·
Had a couple minutes last night to take a closer look. I have an aftermarket CDI enhancer and a fuel optimizer installed. These items are "under the hood" and were covering up some relays on the right side of the battery.

Pretty sure those are the relays I need to test. I'm going to buy some allegator clips today so I can make some micro jumper cables to power the relay with the battery and then test the ohms on the other terminals.
 
#6 ·
I tested the relays last night. I took a couple of pieces of 4 inch wire and attached a female spad connector to them. Using these jumpers allowed me to attach the power and ground connectors and still use the pocket tester to safely reach the other terminals on the relay.

The relays all tested favorable. I switched the handle bar switch with a working one, the relays are okay, and the servo unit spins. Now what?

Has anyone done some testing at the connection point to the servo? There is a long electrical connector with about ten terminals on it. Seems to me that we should be able to run a battery of tests at that location. Any electrical wizards in this forum that could help me?

Jeff
 
#7 ·
Final Update -

Retested the relays. All appear to be okay. Cleaned them with electrical contact cleaner.

Disconnected the servo from the differential and plugged in the electrical connector. Used the switch in different positions and watched the servo final gear turn. All seemed to be okay.

Reassembled everything and put the machine on blocks. 2WD, 3WD, and 4WD all worked correctly.

The only thing that really changed is that I cleaned all the electrical connectors.
 
#9 ·
Thought I had it fixed. Worked for a little bit in the field then failed again.

I bought a new switch and ran it through the settings (2WD, 3WD, and 4WD). Seemed to work again. I'll field test it and report back.

Jeff
 
#10 ·
Please report back. I am going through the same problem right now. I have check the fuses, check the relays. Disconnected the electrical connections from the servo and verified the wiring is good. Pulled the servo. Hint: Drain the front diff first. hahaha

Mine problem started with the wiring from the 4WD and Diff Lock switches crossed, so when I went to switch to 4WD, it switched to the Diff Lock. From that point on, I couldn't get the Diff Lock to release, even after I corrected the wiring. The slide in the front diff moves easily. Need to test the servo this evening. Hope that ain't the problem ($300). Hoping I just need to reset everything manually and put it back together.
 
#11 ·
FIXED !!! Whahoo !!!! Tested the Servo Motor and it was fine. The fix was to reset everything manually and reinstall. With the servo motor off, inside the front diff, take the gear slider and move it all the way to the left. This is the 2WD position. I verified my slider moves back and forth and not getting hung up too. Apply power to the Servo motor so the marked gear tooth lines up with the mark on the base. Reinstalled. Now the switches and indication work properly. Did it several times and it all checks out. Now to get some gear oil and refill the front diff and ready to go.
 
#12 ·
Hopefully this will be the end of my 4wd issue.

I replaced the handle bar switch and did a field test. Seems to be working fine now.

Jeff
 
#14 ·
I am having a very similar problem.

When I turn ignition on the display will show I have switched to 4wd and I can hear the servo motor working.

If I leave it running it will switch back and forth every now and then.

I was riding this weekend at about 90km/h and I was in 2wd but the 4wd indicator on the instrument cluster was on.

I slowed down, stopped shifted gears around and the light went off. No damage as far as I can tell.

What do you all think? Very low kms on this 700. A bit over 600kms.

Changed front and rear diffs and motor oil only once.


Sent from my Yamaha Grizzly somewhere in the Great White North.
 
#15 ·
I'd start by removing all 4wd related connections..servo, relays, switch and putting dielectric grease in them, and reconnecting. This is a good practice with all connections, especially if you're in alot of mud and water. Alot of folks have fixed this problem by just doing that. If that doesn't fix it, I'd look into the switch. Open it up and put some dielectric grease on the contacts and try it again. Not sure what year yours is but this seems to be a common problem on the 14's and 15's. Here is a video of removing and cleaning the switch if it comes to it.