I have a 98 ram 1500 with a 360 gas engine and 173k miles. I am about the 4th or 5th owner and I admit this truck has been ridden hard and put up wet. I have a problem with the 4wd indicator light (or maybe 4wd, not sure). I can shift into and out of 4wd, both high and low with no problem. However, quite often, when I drive in 2wd high, the 4 wd indicator light with flash on and off. This is not a rythmic flash like a warning indicator, but with no set periodicity or timing it just comes on and goes off. It seems to do it more often under deceleration or down hill, but sometimes on flat level ground, the interstate, whatever. I have adjusted the transfer case linkage (this is a floor mount manual shift transfer case and an automatic tranny), but I cannot adjust the linkage far enough to stop this problem.

Any ideas?

 

according to the haynes manual wiring diagram, you have a black/gray wire coming off the back of the cluster and it goes to a 4wd switch, then its a black wire coming off the other side of that switch and i think (not sure) that it goes to the front axle from there. that could be loose or that switch could be bad. my guess would be that a wire has poor contact somewhere. i would pull the cluster out and check the wiring harness that it plugs into to make sure that black/gray wire is pushed all the way into the connector and not loose at all. then i'd follow it to that switch (not sure where it is or what its for) and check the connections there, then i'd go under and check any wires on the cad on the front axle.

 

The lamp switch is located on the front axle (passenger side) at the CAD unit. Check to make sure your getting vacuum there. You could have a short in the switch causing the flashing, or you could have a vacuum leak causing the CAD actuator motor to slightly switch between locked and unlocked.

The front axle CAD is what you want to check.

 

hey i was on the right track, kinda

so start at the cad.

 

Mine once blinked when I had a vacuum leak. The actuator wasn't fully disengaging due to lack of vacuum.

 

Mine was doing the same thing, buy mine is a 2001 5.9, and i found this wire disconected.

 

We were typing replies at the same time, you got in first and you provided more info than me! I'd say I was on the track behind you!

LULZ

 

on the drivers side end of the CAD is a contact switch theat operates the light. start by unplugging and cleaning the mud out of the elec connector. check for loose or broken wiring. there's a contact switch in the end that closes and jumpers those 2 wires when in 4wd. if you jumper them manually, it will illuminate the light on the dash.

if the wiring checks out, you may need to replace that switch, or check vacuum operation, and/or dig into the cad.

don't remove the cluster. the problem is not there.
http://www.dodgeram.org/tech/repair/..._engagment.htm

 

^^^What he said. And if you do have a problem with the CAD unit, replace it with this and never worry about vacuum problems again:

http://www.4x4posi-lok.com/app_dodge.html

 

I gotta say, you guys are awesome! I was sort of skeptical when I posted the original question about getting any help. You guys are all over it!

I'll try all the options posted and let you guys know what I find. THANKS!