da_bigg_wigg

hey there. so my 4runner is currently renamed the 2runner cause i can't engage 4wd. i put it in 4h, and theres no difference. i put it in 4l, and im in 2l. w00t! now, the plan is to get some locking hubs here pretty quick, but ive gotta wait for a good opportunity cause the wreckers want 200 bucks for a set of used ones! (that is in canadian, so its prolly like 12 bucks american or whatever the exchange is now...) now, the light wont even engage stating that im in 4wd. if there was a vacuum hose unplugged would the light not turn on? ive looked around a little bit, but nothing serious as ive been much too busy lately, and to be honest i dont exactly know what im looking for. or is it something more sinister than a disconnected hose? i need your input dudes and dudettes, im new to toyotas and 4wd systems alike. my last and only other car ever was an 86 civic, and although i loved the thing, mudholes proved to be a problem for it please help out this yota newb!

callmej75

An unplugged or cracked vacuum line would cause the light to not come on. Go outside to the passenger side fender and notice 2 vacuum lines running thru the fender. These two control the ADD locking and unlocking. Notice one of the vacuum lines comes off of the side of the manifold over to a check valve mounted in a little holder on the fender and then leads through the fender with the other vacuum line. Start the truck and put it in 4WD and pull the vacuum line off after the check valve and see if you have any suction. if so proceed to go under the fenderwell and pull part of the inner fender out. Notice there is a canister mounted on the front of the frame and those 2 vacuum lines run to it and 2 more come out. Inspect all vacuum lines for cracks. If none is detected then move on to the front of the differential. Notice there is an electrical connection going to a part on the front of the diff and this is the ADD Indicator Switch. You have to pull this out to test it and you have to drain the front diff oil when you take it out or you will have a mess. Here is the schematics and how to test the parts. I would definately inspect the check valve on the fender because mine wasn't working right and I just did the redneck thing and blew through it and spit in it and it has worked ever since and that has been 8 months ago! http://personal.utulsa.edu/~nathan-b...26addcontr.pdf

da_bigg_wigg

thanks dude!

callmej75

anytime...have any other questions feel free to ask!

Flamedx4

Agreed with checking the vacuum lines and elctrical connections first. The ADD mechanical part on the axles is darn near bulletproof, no reason to really worry about that.

4Crawler

iTrader: (3)

This page should give you all the troubleshooting and repair ideas you need:
- http://www.off-road.com/toyota/tech/add/index.htm

Or this one on how to eliminate the ADD altogether:
- http://www.4x4wire.com/toyota/tech/add/

da_bigg_wigg

well, vacuum hoses appear to be ok. still no vacuum. solenoid isn't getting any power. i looove fixing electrical stuff...

callmej75

Could possibly be the relay under the dash.

da_bigg_wigg

great. looks like thats what im doing tonite. to add insult to injury, i found that one of my cv boots is torn, and also there is a plug on the drivers side of my tranny (or transfer case, actually i forget) that has a pair of wires running into it. anyways, the red&black one is basically cut through. must of hit a stick or something. ill try repairing that first. if it is the relay, exactly where behind the dash is it?

callmej75

I'd say get those wires reconnected and then try it...its all it could be. the relay cost me $80 at the dealer.

squishy321

if one of the wires is cut i would bet good money on that being it. If have a scenario and a question. I have a 93 4runner, ADD equipped , and i put in a non ADD tranny out of a 89 4runner. Anyways when the time came to put it in 4 wheel drive just after putting in the new tranny, nothing happened. Then i realized that i left the wires unhooked, but this "new" does not have wires for ADD, hmm. There is a wire coming out of the transfer case that turns on the light to the dash, but there are two wires coming from the ADD, I'm assuming one is for the ADD itself and one is for the light. Anyways i just hooked both of them up and everything works fine except my 4wheel drive light stays on in the dash, and i get ppl saying "hey your in 4wheel drive" and i have an excuse to ramble on about my tranny swap. Anyways big wigg this sounds like your situation, and my question is can anyone see any harm, electrically, about the setup i have here. PS its been working well for about 4 months so im leaning towards no.