4wd buttons flashing

[Skahide]

I have a new to me 1998 yukon w/ auto 4wd. Only the 2HI button stays solid when selected. The light next to "Neutral" never lights up. The Auto 4wd, 4HI, 4LO buttons just continously flash when selected. I have replaced the button selector and the 4wd actuator with new parts.....with no change.

I can hear the actuator clunk if I press 4LO first, and then clunk again if i push the 4HI after. If I press the 4HI first it never makes a noise.

 

[972sparky]

I think there is 2 actuators, one on the transfer case and one on the front axle. Need to make sure they are both working, and the limit switches are good as well. The lights flash if the limit switches do not detect the actuators in the right position for the selected mode. A lot of the front axle ones around that year were "thermal" and did not make much noise (clunk) as the "solenoid" style does. Also the thermal did not work well, mostly when cold outside with snow and ice when you need them most. I had a 1996 K1500 with the thermal, replaced at least 4, them changed to the solenoid style and never had another problem.

 

[swathdiver]

I have a new to me 1998 yukon w/ auto 4wd. Only the 2HI button stays solid when selected. The light next to "Neutral" never lights up. The Auto 4wd, 4HI, 4LO buttons just continously flash when selected. I have replaced the button selector and the 4wd actuator with new parts.....with no change.

I can hear the actuator clunk if I press 4LO first, and then clunk again if i push the 4HI after. If I press the 4HI first it never makes a noise.

Gotta get a scan tool on this to pull the internal codes and run proper tests without throwing time and money away.

 

[TheBigler]

I have the exact same issue and process of events with my 97 2 door. Did you ever get this fixed? If so what was the cause