'97 773 Aux Hydraulics Problem

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davimac424

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Sep 17, 2014
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2
Hi, I have a '97 773 and am trying to diagnose a problem with my aux hydraulics. When I bought the machine both coils on the control valve were unplugged. I plugged them back in and one of them is stuck open. I assumed that the stem was stuck but did some electrical troubleshooting before removing any stems. What I found is that when the key is in the run position or in the relief position, one of the coils is always energized. When the key is in the off position, both coils do not have power (normal). With the AUX keypad turned on, locked, switch moved either direction, or the trigger pulled, one of the coils is always energized. The interesting thing is that when I pull the trigger with a test light on the positive pin and I have the aux locked on the button pad, the bulb gets dimmer and brighter each time I pull the trigger. If the aux is on but not locked, the light gets dimmer and brighter when I push the toggle switch one way. Also, I can hear a small click in the PWM when I pull the trigger each time. This leads me to believe that the switches are not the problem. On a side note, I removed both coils and tested them off the stems and they both work. Sorry for the confusing description of the problem, any help will be hugely appreciated. Thanks, David
 
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davimac424

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Joined
Sep 17, 2014
Messages
2
I figured it out on my own and here's the answer in case anyone has a similar problem. The ignition switch has a terminal labeled ACC which is energized when the key is turned backwards and relieves hydraulic pressure to the aux fittings. Either someone installed the wrong switch in my 773 or the switch had failed, and it was sending power to one of the aux coils when the key was turned left or right. Figured it out with a test light, installed a new $28 OEM switch, and everything works as it should again. Hope this helps someone else.
 

Tazza

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Dec 7, 2004
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That is an odd one, i don't think power should be going to any coil till the thumb switch is activated. It's almost as if the switch is not working just right, when in the centre no power should be going to the coils. If it is a PWM style, the more you move the switch the more power (pulses) goes to the coil.
 
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