Getting no 4wd

Hey there, hoping someone with more tacoma knowledge than I can help diagnose this issue.

After about 6 months of no 4wd operation, I went to cycle it today just to keep things moving since it had been so long. However, I got no 4wd indicator light on the dash.

When I press the 4x4 button I can hear the actuator doing something but im getting no light on the dash. I was also able to get it in low-range and turn on the rear Dif lock.

Im wondering if this is just as simple as a dash bulb? or is the front actuator not relaying?

4wd fuse still fine too.

this is a new-ish to me truck and the first ive owned that had any sort of electric 4x4 selector, so any advice is helpful

EDIT: its a 2002 Tacoma 4x4 SR5 5-speed

 

What year is it?

 

Your front actuator is likely stuck in the disengaged position.

Try connecting a hand vacuum pump (something like the pic below), to one of the two vacuum line ports on the front diff actuator (if you have them), and apply enough vacuum to try and make it engage. If it's an entirely electronic actuator you'll need to remove the actuator from the diff to get it unstuck.

 

If you do end ups pulling the front actuator. Add a bead of gasket maker around the oring when you install it. I have replaced a few of those because water has gotten in to them.

 

duh! sorry everyone, its 2002.

 

Makes sense. Thanks!

 

95.5-00 are vacuum actuated and 01-04 have electronic actuator.

How far did you drive while trying to engage 4wd? It's not automatic 4wd as soon as you depress the 4wd button. The clamshell 4wd slide gear must aligned to engage, which may take 10-20 ft of slow driving forward.

 

Yea, thanks. I drove it plenty more than that. Tried forward, reverse, etc.

I am now wondering: Would RR Diff Lock turn on if the 4wd is not engaging? I was always under the impression that because its all electronic in this truck, it would not turn on without the truck being engaged in 4wd but maybe I'm wrong.

 

Unmodified, elock will only work on 4lo. It's just a position switch, safety feature.

Grey wire mod done = anytime lock.

Engaged 4wd, Jack up the front end and spin the front shaft and see if the front tires spin.

 

Makes sense.

Unfortunately dont have a great place to even jack the truck up right now so I'll report back here once I can.

But I was able to at least confirm the front drive shaft indeed locks when you engage the 4wd button. But still not even a flashing 4wd indicator on the dash which seems weird to me.

 

I think the diff lock will engage so long as you're in low range, whether or not that's 2-Low (like yours where the front diff isn't engaging), or 4-Low.

I know that was the case with my '98 4Runner, when my front diff actuator wasn't working.

 

This is what I was wondering. Thanks!

 

Was able to finally look at it yesterday and...

4wd is definately not engaging in the front actuator. When the 4wd button is pressed, you can hear the actuator on the t case do its thing, and the front driveline locks. But the front diff is not locking into 4wd. After messing with it and tapping it with a hammer, I was able to get it into 4wd and back to 2wd three times in a row, but have yet to get it to engage again.

Does anyone know what the typical thing these front actuators do when they are going bad. This truck has the electronic actuator, not the vacuum one. So I am wondering if this is something with the electical signal coming into it, or do you think they just work intermitenly when they are going bad??

 

I'd check the 4wd position switch on the transfer case, as there's a chance it's bad and not telling the 4wd ECU that the tcase is engaged and therefore wont send a signal to the actuator (this isn't likely to be your issue, but better to rule it out before the next step).

Next step will be to pull the actuator and inspect inside of it. Might be gummed up. You may get away with cleaning it good, reassembling it, and being good to go

 

Great advice, i did mine on my 2019 when I bought it. These actuators will take on water.

 

Transfer case indicator switch solved the problem! Pulled it and tested for continuity - none!

Thanks everyone here who helped diagnose!

 

Awesome! Glad you got it fixed!