No 4X4 light on dash

[satmike]

The 4X4 light on the dash dosen't go on when shifted into 4X.
the transfer case does shift but no lights. All the other idiot lights work.
Any Ideas?
Thanks Mike

 

[DenverPilot]

Lightbulb burnt out? ;-)

 

[Missouri Mule]

Have to agree. If your front axle is operated by vacuum like my 96 then it could be the switch on the front axle where the axles connect together.

 

[DonFitzwater]

Pull the switch out of the cad and manually manipulate it. If the light comes on, you’ve likely got a shift fork travel problem. If the light doesn’t work, it could be the bulb as mentioned.

 

[satmike]

The light works manually. Has anyone used one of these?



https://www.summitracing.com/parts/pos-400/questionsanswers/#qa-display-detail

 

[VolsFan]

The light works manually. Has anyone used one of these?



https://www.summitracing.com/parts/pos-400/questionsanswers/#qa-display-detail

Yes, get the posi lock kit, you won't regret it. I also got mine from summit. I had the exact same issue you describe then lost 4wd when I needed it. Ditched the vacuum set up. It isn't as easy to engage 4wd but it is reliable

 

[DonFitzwater]

They also make a kit to permanently engage the center axle disconnect. I did it on my 94 plow truck about 5 years ago. It’s been great. Shift the lever and bam, 4x4 instantaneously engaged.

https://www.morris4x4center.com/all...UKJzg58Ozczog8aAojxEALw_wcB&gclsrc=aw.ds&ab=a

 

[HHhuntitall]

The standard fix, after diagnosing the problem isn't a vacuum line problem, light, or sensor, is to replace the vacuum actuator. It's actually a common failure, in my experience.

The mechanical engagement kit is a nice kit. I've also replaced the spider gears and used a solid axle out of a later 2001-2002 that had a solid axle shaft without the actuator. Then there is the expensive free spin kit.... it all depends on how you use it and what cost you want to spend on fixing it....

 

[Tractorat]

Not quite the same thing, but is it possible for the light to come on but the truck has not actually gone into 4WD ?

 

[JR]

Have you looked at your vacuum lines? if they're rotted or the rubber portion has dry rotted you won't have enough vacuum to operate the actuator. I've seen the vacuum switch on top of the t case fail a few times also but mainly due to corrosion. Just another thought.

I had the posi Lok kit and I was never very impressed with it. Could never get it to engage or disengage with out a lot of fenangling.

 

[HHhuntitall]

I have, on rare occasions, seen the vent line (green line from the T-case four way plug up the firewall) get stopped up, not allowing the diaphragm in the actuator to move either way, as it's basically vapor locked with vacuum on each side, as it can't vent to the outside to let vacuum off either side.... it's hung in neutral.... you can test the actuator with a vacuum pump or brake bleeding tool to see if it's actually moving either way.

 

[twopipes]

I live in NC North of Charlotte, so I don't get too many opportunities to use 4-wheel. However, I did last year and the 4-wheel lite would not come on or engage. My local fix-it guy said that the vacuum actuator shaft was stuck. He unstuck it by tapping on the diaphragm and suggested that I exercise it periodically. I put it in 4-wheel 3 or 4 times per year when I'm going in a straight line for a short time and have never had a problem again.

Good luck.

 

[Woodenhead]

The vacuum system for the front end is a problematic system, typically it's either bad lines, a leaking diaphragm in the CAD actuator or a sticking vacuum switch on top of the transfer case. At one time I've had each of these problems so I replaced it all with the posilok cable setup and it's been working fine ever since. As an added bonus you can use it in 2WD Low Range which is nice for jockeying trailers around, especially with clutch.