I have a 1998 gmc 2500 diesel 4x4. The 4x4 light flashes when try to switch into 4x4. the transfer case is engaging but the front actuator is not. bought new actuator still not working. This is a 4 wire actuator and there is 12volts on the brown wire all the time. there is continuity through the wire harness. Can i apply 12v to the actuator manually to test? which wires should be 12v and ground?
Do you need more info?
Country: CanadaMake: GMCModel: Sierra 2500 HD SLYear: 1998Engine: 6.5 diesel
Hi my name is Hal.
Let me research that for you. Be right back.
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Here is the front axle diagram for the auto shift transfercase. If yours is manual shift, or does not have the auto position please let me know.
Here is the diagram for the electric shift transfercase ( no auto) front axle diagram.
Here is the diagram for the manual floor shift, front axle diagram.
Mine is an automatic with the electronic push button 4x4. I read about a problem similiar to mine on your web site. There is a Lt Blue wire (mine does not have a Lt Blue wire) at the transfer case switch which they said should have power with the key on and 4x4 engaged. This is supposed to put power to the White w/Black stripe wire at the front actuator. There is no power to my transfer case switch.
I have removed and checked the transfer case switch and it seems fine.
I do not have the Auto - 4x4 button. Only 2 Hi and 4 Hi and 4 Low.
Do you know where the 4x4 relay is that is shown in diagram?
How can I check the actuator by itself?
You have the electric shift transfer case.
This is the diagram you use.
It shows the insides of the front actuator. Power on the brown wire is good. This comes from theXXXXXfuse.
Ground comes from terminal B Gray wire with black stripe.
Here is a diagram showing the internal circuits of the actuator.
Here is the transfer case switch circuit diagram.
31 yrs dealership technician.