Has anyone had any luck cleaning or otherwise servicing the four wheel drive electronic components to see if that stopped dash lights blinking and failure to fully switch into or out of 4wd? I'm getting the 4wd dash light blinking at random times...the center light starts to blink after several miles of 2wd or 4wd driving, randomly.

I rarely use the 4wd (just on occasion in snowy winters or muddy road conditions). It did this last winter and it seems to effect going into or coming out of 4wd mode. My fix was to turn the car off, turn it back on, and then place it in/out of 4wd and that seems to work for now. I'm unsure if this is a connection or sensor on the center differential, front differential, or the larger switch near the passenger front fender.

I want to know if cleaning any of these might correct the problem, and which one to try first for the center differential blinking dash light.

 

Directly underneath the airbox that holds your engine air filter there is a pair of solenoid valves. That controls the front axle from being on or off. What happens is the valve goes bad and allows air to bleed off from the storage tank on the front axle. When this happens, it engages the front axle. More interestingly, it can cause excessive wear if not address sooner rather than later because the mechanism is only partially engaged when the leak down is occuring. There is a way to ground the OBD port to make the center diff light flash out the code. If code 35 returns, it is an implasable engagment (the front axle is engaged when the 4WD lever is in 2H).

 

Thanks! I was wondering about that. I haven't noticed any tire grabbing on dry pavemet or noises, or tire wear. Hopefully mine has just been the light. It did this for the last 7,000 miles, on and off. Usually is off at first and pops on about 15-20 miles of drivjng.

 

There wouldn’t be any tire grabbing in our case. The 4H does allow you to drive on pavemet. Essintially inside the transfer case there is a viscous coupling unit that splits power between the front and rear wheels automatically. (Makes it an AWD vehicle) The modes you never use on dry pavement is 4HLC and 4LLC. Both of those modes lock the center diff and change the stability control for off-road driving (if you have an 03’ or newer, older ones have a limited slip diff in the rear)

 

I had this issue and found that the vacuum line which comes off of the back side of the intake manifold inlet, which leads to the two aforementioned solenoids, wasn't replaced after the recent spark plug replacement project. Reinstalled the hose and the diff light hasn't blinked since.