Hello,

When at a complete stop my 4 wheel drive light is off. When driving it is either flashing very fast or just staying on. The 4 wheel drive is off. When I put the vehicle into 4 wheel drive the light will stay on. Have tried several time putting it in and taking it out of 4 wheel and no go. Any suggestions would be appreciated.

Wade

 

Their is a sensor on the CAD(unit is located on the axle) it turns that light on and off sounds like it's going bad.

 

I was having a similar problem and it ended up being the vacuum switch in the transfer case sticking. It's just screwed into the top of the case and has a big plug with 4 vacuum lines coming out of it. Just pull off this plug and use a 27MM deep socket or wrench to take it out. Be careful you don't break off the nipples or you'll have to get a new one like I did.

It's probably partially or totally stuck in. Take it out and clean it off thoroughly, probably with electrical contact cleaner (others may have better recommendations on cleaners), until it moves freely. If that doesn't work the part isn't very expensive, though most parts houses appear to have to order it (15-20 bucks). Taking it out to clean it is more or less free, though.

 

i'm going to guess your 4wd indicator switch on the drivers end of the CAD is flopping back and forth, giving you a false indication of 4wd. unplug the elec connector and remove and inspect the switch and see if it needs a good cleaning. the cad shifting fork is supposed to slide over and depress/contact that thing (make continuity). when in 2wd its supposed to be open. new switch is available at any parts store for $15-20.

 

Mine did this when I had a vacuum leak. The vacuum actuated switch wasn't disengaging fully, causing the intermittent 4x4 light to come on. Another tell that you have a vacuum leak is when your air shifts from forward vents to defrost vents when you give the truck full throttle.

 

how do you fix this vacum leak? I have the same issue!

 

You have to find the leak first, which is the hardest part. Do a search, lots of people have posted where they found their vacuum leaks.

 

add it to my list of crap to do this winter!!

 

well i guess i have the vacuum leak, mine goes to the defrosters everytime i go to about half throttle. but only ssometimes and my 4wd light is on constant, doesnt matter what the truck is doing, parked, going down the road, doesnt matter

 

If you have cruise control, there is also a hose(s) under the battery tray to look at.