subitoy

Having issues with engaging 4WD on my 97 LTD. When I push 4WD button on a lever I don’t hear any clicks and green light showing 4WD does not turn on. I checked for 12V on ADD solenoids and VSV2 has 12V and VSV4 does not have power. Vacuum houses look fine. 4WD works after 10-20 attempts and I have to let go of the gas pedal right after pushing the knob. When 4WD finally engages green light is on and VSV4 solenoid has power. I was looking into schematics for 97 LTD and can’t find information I’m looking for. Haynes repair manual don’t have schematics either. I want to know how circuit goes from pushing 4WD know to the point of powering VSV4 solenoid. What will affect powering of VSV4 solenoid after pushing 4WD button?
I ruled out the 4WD switch on a lever by checking for continuity. I never have problem of going out of by pushing the 4WD button and green light never flash. Also once 4WD is on I can drive for days and unless I push button it will not disengage itself. Thank you for your help.

scott d

I've had a little trouble with my 97 not going into 4wd as well. Mine has only done it a couple of times, and both times I tapped on the solenoid that engages the 4wd and then it engaged.....which makes me think that it is the solenoid itself which is the problem.

subitoy

Thanks for the tip.. The only issue is that I don't have 12V to the solenoid and my understanding is that 12v should power solenoid to turn on. That's why I'm looking for schematics to find out what regulates power to solenoid.

subitoy

The problem still persist, just found the diagram in case someone else is looking for one. Will update once I'll figure out what's wrong.
http://www.diakom.com.ru/CAR/Toyota/...RAMS/12029.pdf

Simann

Have you tested your 4WD button/switch on the shift knob? Sounds like you've tested everything else.....

EDIT: Never mind, saw you ruled it out. Sounds like one of the 5 transmission/transfer case sensor/switches that could be on the way out. Get under your truck, test the two switches on the ADD actuator, and the one switch on the front diff ADD actuator. Exactly 3 of my 5 switch/sensors were dead. (My problem was the ADD actuator all along though). If you follow that wiring diagram you will surmise that to get the 12v power to the ADD solenoid, the signal must initialliy be passed through the switches to tell the ADD computer what position the vehicle is already in. Again, get under there and check those switches, they are wear items and will build up tramission oil inside of the switch that can intermittently cause loss of contact and ultimately loss of signal.

Switches are Part#:

84222D, 84222B, 84222F, 84222-No.1, 84222-No.2

From this site to order from: http://www.villagetoyotaparts.com/sh...&searchString=

subitoy

Thanks, Yes, I have checked that button and it works fine.
Just recently came by this thread and will need to do bunch of other checks. 4wd have been working fine for the past 2 days so I'll have to wait till it stops working again and do some more tests.
http://www.ttora.com/forum/showpost....6&postcount=36

subitoy

Problem resolved. Once 4wd was engaged I was driving for a week without disengaging. After that I would leave it on while parked and it turns on a fly no problem now. I have not been using it last summer as manual says 10 miles each month so some switches probably stuck because of no use. Spring is here so no use for 4wd for us who use it only for snow so lets not forget to keep using it!

vegaskurt

If it happens again, you can get a hand held vac pump from Harbor freight for about $9. Attach it to the diaphragm, pump it up, then repeat on the other port of the diaphragm. Once you get the parts moving you should be good for a few months.

I had to do this in the beginning of each winter after not using 4wd for awhile. If anyone needs those solenoids shoot me a PM, I have no use for them now.