Maybe an easy one for the techies in here:

My good friend Chris , who unfortunately has a very limited command of the English language, asked me to post a question regarding the 4x4 control lights on his '99 3500 Cummins Dually.

After having had the vacuum unit exchanged by the garage (not a Dodge expert!) the control light do not seem to work properly anymore.

When engaging 4x4 the red control light only goes on no matter if 4WD-Lo or -Hi is chosen; the green control stays off all the time.

Can anyone in here shed some light on the exact meaning of the two control lights, i.e. when they should be on and when off, and what probably needs to be done to get the function back right?

Your help would be much appreciated
Thanks
Tom

P.S.: You may want to answer directly to Chris' thread "Allrad-Probleme" within the German US-Car-Owner-Forum. Your answer in English would be fine as someone would translate for Chris.

 

No one around who could answer this question or do I just expect too much of you guys???

Cheers
Tom

 

I'm not sure what two lights you're talking about. Maybe it's something on the newer trucks, because I only have one...and it's orange [>:]

Does the truck actually go into 4wd? Is this just an issue with the lights? Did this just start happening after he had the CAD unit swapped out?

 

I have a 97, and I know the interior is diffrent than a 99. But mine has 1 light that says "4WD". Thats it. But I believe the control for the light is on the transfer case. Check the linkage on the trans case. Check for any wires that are pulled off or aren't pluged in. This could be the problem.

 

4WD is working properly after the change - my friend is just concerned about the green control light not working after the swap.

My '94 has an orange light for 4WD only too.

 

Thanks. I have translated your hint and forwarded it to Chris; he will check accordingly
Tom

 

did he replace the cad system with a posi lock or with a new cad. on the cad itself. there are a few vacume lines. there should be a yellow and a red one on the passenger side of the unit. one of them could be cloged and not alowing it to ingage. there are hard line that are also attached to it that run along the frame ( on the Passenger side) and in front of the trans cross brace. if they are pinched it wont work. try taking off the hose on the righ and see if it ingages. if that the case you need new lines. there is also a vent line and a plug on the left side of the unit. I can get you a pic later on when you need it.

 

He said the 4wd is working properly

This just seems to be a light issue. And so far none of us responding have had a 2nd light [>:]

 

oh then it could be the bulb is out or the connecter is out or dirty.

 

I doubt that actually since the bulbs have not been touched though... Let's see what Chris comes back with according to the proposed checks on the connetors on the tranny...

Cheers
Tom