I need help! I don't have 4WD on my Daihatsu Hijet because the front axel lock is not coming on. When I press the button on the 4WD shifter, I hear some vacuum sounds under the seat, and the actuator in the rear works, but the front actuator does not actually push out to engage the axel lock. I tested the button and it is good. No green light is coming on on the dash though. I've read that it can be a problem with a switch or something behind the dash? Can anyone tell me exactly where the problem might be? Thank you!
I think there is a switch on the vacuum units to indicate they are engaged. First thing to do is see if the front unit is getting vacuum. There is a vacuum switching valve controlled by the switch at the dash, which triggers teh vacuum switch. this then sends vacuum to the engage side of the unit on the axle, and pulls it in. When you turn it off, the vacuum valve flops, and then applies vacuum to the other side of the chamber and pulls it out. Vacuum tubes get old, dry out, and crack. this is more likely than the electric going bad. Particularly since you can hear the valves for the fron axle doing something. The valve for the rear axle is in the back.
I just replaced all of the vacuum lines going to the solenoids. Still seems like something electrical.
There’s a 2 wire switch on the transfer case in the back at the top that senses the transfer case lever is “locked” if it doesn’t see that it won’t lock the front driveshaft fork in the transfer case/ turn on the light You can use a jumper wire and If the light comes on and the driveshaft locks in then it’s that switch has gone bad , seen a few crap out
There is a contact switch on top of the transfer case, right behind the 4 wheel drive control mechanism. Screws into the transfer case. After replacing almost every vacuum hose and tracing every wire in 4 wheel drive circuit, pulled every wire connector and cleaned, tested every vacuum solenoid, I tracked it to that switch. 2 weeks worth of persistence. 4 wheel drive works again. Little bugger looks like this.
