2002 sequoia very odd 4x4 issue
09-03-2017, 04:19 PM
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2002 sequoia very odd 4x4 issue
I bought a 2002 sequoia pretty cheap with a 4x4 issue, it would go into 4wd just fine but you had to hit the transfer case actuator with a hammer for it to come out... We all know percussive maintenance is degenerative.
I took the plastic housing with the motor off the actuator (being careful to leave the gear on the transfer case end so as not to lose the positioning).
Turns out the problem was one of the magnets in the motor had come loose, for whatever reason that would let it easily spin one way but not the other. No big deal, fixed that.
Now I have a very strange issue. It'll go into 4wd fine, but when I go back to 2wd, the actuator only spins half way and stops. If I take the plug off and jump 12v directly to the motor, it happily goes the rest of the way to 2wd. When I plug the connector back in, the front diff unlocks and all is well. It will then go into 4wd just fine, and repeat.
What did I screw up to cause it to trigger a stop only half way shifting back into 2wd??? All the little metal contact springy things look good and are contacting, I'm kinda lost here...
I took the plastic housing with the motor off the actuator (being careful to leave the gear on the transfer case end so as not to lose the positioning).
Turns out the problem was one of the magnets in the motor had come loose, for whatever reason that would let it easily spin one way but not the other. No big deal, fixed that.
Now I have a very strange issue. It'll go into 4wd fine, but when I go back to 2wd, the actuator only spins half way and stops. If I take the plug off and jump 12v directly to the motor, it happily goes the rest of the way to 2wd. When I plug the connector back in, the front diff unlocks and all is well. It will then go into 4wd just fine, and repeat.
What did I screw up to cause it to trigger a stop only half way shifting back into 2wd??? All the little metal contact springy things look good and are contacting, I'm kinda lost here...
Last edited by chrisgt; 09-03-2017 at 04:21 PM.
09-03-2017, 05:24 PM
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Ok so, I sort of found my problem, it's the two position switches on the top of the actuator rod.
I don't quite understand why there are two different 4wd positions in the transfer case however... The front switch works fine going INTO 4wd, but isn't sending a signal coming OUT of 4wd, thus it gets stuck shifting in the middle. Jumper the connector to the front switch and it finishes the shift...
And yes, if I unplug it, it gets stuck going into 4wd, so I know it's working one way...
Why in the world would that sensor only work going in one direction is beyond me... I took it out and pushed it with a multi-meter, and it has continuity.
Anyone think a new switch would solve the problem, or is something weirder going on here... Also, why two switches that both trigger at the same time? Any reason not to just, you know... wire them together?
I don't quite understand why there are two different 4wd positions in the transfer case however... The front switch works fine going INTO 4wd, but isn't sending a signal coming OUT of 4wd, thus it gets stuck shifting in the middle. Jumper the connector to the front switch and it finishes the shift...
And yes, if I unplug it, it gets stuck going into 4wd, so I know it's working one way...
Why in the world would that sensor only work going in one direction is beyond me... I took it out and pushed it with a multi-meter, and it has continuity.
Anyone think a new switch would solve the problem, or is something weirder going on here... Also, why two switches that both trigger at the same time? Any reason not to just, you know... wire them together?
11-09-2017, 08:33 AM
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Just starting the trouble shooting process on the same, a 2002 Sequoia 4.7L. Truck will not come out of 4X4 and the center indicator lamp continues to flash, regardless of methods used to coax the beast to be released back into 2WD. Front transfer case A.D.D. gearbox opened, cleaned up a bit, and re-greased. Pins on this motor/gear are 6-5-4-3-2-1 (left to right when looking AT the connection at the gearbox). Internal to the motor/gearbox are electrical traces that do the yota magic switchology. Jumping pins 4 to 5, positive 12v to 6, negative to 1 runs motor one way. To reverse, move +12 to pin 1 and ground to pin 2. This tests the motor/gearbox and the travel limits (made by the internal electrical traces).
I'm onto the electrical manual and the Transfer case next. Parts diagrams from the yota stealership's parts departments are quite vague, especially when try to gain switch part info. as in: what does this transfer switch do? and what does that second switch do? (specific identity).
Any help will be appreciated. I'll follow up with my findings, too.
I'm onto the electrical manual and the Transfer case next. Parts diagrams from the yota stealership's parts departments are quite vague, especially when try to gain switch part info. as in: what does this transfer switch do? and what does that second switch do? (specific identity).
Any help will be appreciated. I'll follow up with my findings, too.
11-09-2017, 09:58 AM
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Both the switches on the transfer case have to be triggered when the actuator is in the 4wd position, if one of them isn't working, it'll get stuck in the 4wd position. Unplug them when it's in 4wd position and check the continuity of the sensors, they should both be closed. If one is open, that's your culprit. Plug in the one that works and with the key on and the light flashing, short the terminals of the one that's acting up. It'll go BZZZZPT and click out of 4wd into 2wd or awd, depending on which direction it was trying to go. The sensors from toyota are kind of expensive, but the ones from Dorman are garbage and will fail in 2 weeks... don't ask me how I know
11-12-2017, 09:24 AM
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Well ... progress! As I mentioned, I removed, cleaned, an lubed the A.D.D.
With guidance from Christgt, I next looked at the 2 position sensor switches on top of the transfer case. After removing the wire connections (a bit of a 'squeeze' on the 'top' and a very slight pry upward to separate the connector from the switch), I did bit of soft wire brushing to clean the area prior to removing the switches. Each switch, starting with the most rearward was EASILY removed using a 1/2 drive ratchet and socket. The switches have aluminum washers that needed some cleaning/slight filing to remove the corrosion. The switches each sounded "gritty" when being depressed by hand. The rearmost switch ohm'd out fine, the forward switch had 45 ohms resistance when closed... not good.
Each switch creates a bit of pressure within as the steel ball 'follower' moves in and out. This pressure is relieved through holes that can barely be noticed at the area where the switch body is rolled to retain the steel ball. Air is expelled when the follower ball is depressed and air drawn back in as the follower ball is extended. Along with that air comes in moisture! I drowned the switch with contact cleaner while rapidly activating the switch on and off by depressing the roller ball by constant spraying in the area and holes at the base where the roller ball is retained within the switch housing.
To lubricate the internal switch and to provide future protection from corrosion, I let ACF-50 weep into the breather holes while constantly actuating the switches. (https://learchem.com/products/acf-50.html (no connection other than I LOVE the stuff!) ) A tiny bit of anit- seize on the tread and gasket and the switches were reinstalled. A good amount of dielectric grease was applied directly into the female connector and some onto the plastic body.
Perfect results! the 2002 Sequoia 4X4 works great! If anyone is having issues with the dreaded "FLASHING " light (incomplete transfer into either 4X or 2X modes), and because of the ease and the probable need for some preemptive maintenance, I suggest starting at the two switches on top of the transfer case.
Yet to go is to clean and di-electric grease all of the electrical connections on the vehicle, especially the underside.
With guidance from Christgt, I next looked at the 2 position sensor switches on top of the transfer case. After removing the wire connections (a bit of a 'squeeze' on the 'top' and a very slight pry upward to separate the connector from the switch), I did bit of soft wire brushing to clean the area prior to removing the switches. Each switch, starting with the most rearward was EASILY removed using a 1/2 drive ratchet and socket. The switches have aluminum washers that needed some cleaning/slight filing to remove the corrosion. The switches each sounded "gritty" when being depressed by hand. The rearmost switch ohm'd out fine, the forward switch had 45 ohms resistance when closed... not good.
Each switch creates a bit of pressure within as the steel ball 'follower' moves in and out. This pressure is relieved through holes that can barely be noticed at the area where the switch body is rolled to retain the steel ball. Air is expelled when the follower ball is depressed and air drawn back in as the follower ball is extended. Along with that air comes in moisture! I drowned the switch with contact cleaner while rapidly activating the switch on and off by depressing the roller ball by constant spraying in the area and holes at the base where the roller ball is retained within the switch housing.
To lubricate the internal switch and to provide future protection from corrosion, I let ACF-50 weep into the breather holes while constantly actuating the switches. (https://learchem.com/products/acf-50.html (no connection other than I LOVE the stuff!) ) A tiny bit of anit- seize on the tread and gasket and the switches were reinstalled. A good amount of dielectric grease was applied directly into the female connector and some onto the plastic body.
Perfect results! the 2002 Sequoia 4X4 works great! If anyone is having issues with the dreaded "FLASHING " light (incomplete transfer into either 4X or 2X modes), and because of the ease and the probable need for some preemptive maintenance, I suggest starting at the two switches on top of the transfer case.
Yet to go is to clean and di-electric grease all of the electrical connections on the vehicle, especially the underside.
