1996 3500 4WD dash light flickers

[D.H.]

When driving in 2WD the amber 4WD light on the lower dash left of the steering column flickers off and on. Why might that happen and what course of action is required?

 

[Wiredawg]

on that year truck, it's likely a switch with bad contacts, bad ground, corroded connector, damaged wire, even bad bulb. If you dont have a FSM, a must for me, you need to start methodically checking. Find the switch and check both sides of it with a multimeter (preferred) or test light.

Does it flicker while in motion, truck running at idle, ignition switch on, but not running or all the time while shifter in 4wd. With truck off, ignition on run, try shifting in out of 4wd rapidly contacts in switch could be dirty, corroded. If no good, perform testing as I mentioned above.

Let us know what you find.

Cheers, Ron

 

[D.H.]

First let me thank you for your service and judging by the years you put in we might have crossed paths if you spent any time in Saigon, USARV Long Binh, MACV, and more.

The only time I notice it flickering is when driving in 2WD. I only use 4WD while clearing land.
I plan to have the tracking arm bushing replaced Monday. Maybe the mechanic will understand your testing procedure.
Thank you!

 

[Wiredawg]

You're Welcome! I served from 1976 (6 days out of high school) to 2006. Thank you for your service.

With your further description, I'm guessing it's the selector switch, could even be a slight adjustment of the xfer case shifting linkage.

Please let us know what it turns out being.

Cheers, Ron

 

[Road Dog]

The 4WD lamp is controlled by a switch on the CAD (centre axle disconnect) which is a module on the passenger side front axle. The CAD has a vacuum actuator and a sliding collar to connect/disconnect the axle half-shaft.

The switch could be broken or need adjusting or the wire harness to it could be damaged. Or the CAD is damaged and the sliding collar is moving around. At least it's easy to inspect.

 

[BigPapa]

I’ve had the 4WD light in my cluster flicker, too, and my trucks NOT 4WD! It did it for about a month several years ago. I only noticed it at night. I never did find out why. I always figured it had something to do with the wiring we had to do for the 12-valve transplant.