Hi everyone, newbie here. I have a 92 Dakota V8 4x4. Just recently it will not engage 4 wheel. feels like low range works, but front axle is not engaging. the light for the indicator bulb will not light, but when I check it with a test light one terminal of the socket has power all the time. No power at the switch on the front axle. open for thoughts or suggestions

 

The front axle actuator is vacuum controlled not electrical. This site will help you a lot. http://www.walt-n-ingrid.com/modifications.html#4x4

 

what if there is no vacuum at all, is the switch on the transfer case

 

Yes the switch is on the transfercase. There should be vacuum when engaged in 4wd. But only on one hose I believe.

 

it fixed itself and started working. Bought the vac switch on t/case just in case. stopped working again. put switch in still inop. checked for vac at actuator on front axle, very weak. could find no vac leaks. now 4 wheel light comes on even though 4 wheel does not engage

 

you can try checking to make sure you front driveshaft is turning when transfer case is engaged. I had the same problem on my 90. I took a piece of weedeater string and made sure all the lines were clear and not pinched and changed the vac switch on mine and it started back working. That accuater on the front is not cheap if that has to be replaced.

 

I have plenty of vacuum to the canister at the front axle, and the drive shaft does turn. I believe it is the canister itself that is bad. can not find one in the junk yard and dealer says it is unavailable. anyone have one to sell or a suggestion

 

Junkyard will be best bet. It would be a front axle disconnect Actuator.

Try www.autozone.com www.napaonline.com http://www.rockauto.com/ www.ebay.com

Or try OEM parts site. Go the the FAQ get the part number for it. Then check these sites.
https://www.dodgeparts.com/oe_parts_...e2cf8fa4e8846c
http://www.moparpartsamerica.com/par...?siteid=214583

 

Ok, let's update. bought a vac guage and tested the front disconnect actuator. held vac. on both sides. everything appears to operate properly but still will not engage. 4 wheel light does come on when tring to engage. does anyone know how much the vacuum should be at the actuator

 

the diaphram could be bad.. my truck sat for a yr waiting for a new trans and now wont work in 4wd so i need a new diaphram.