center differential

[PHAEDRUS]

Hey everyone,
for the newbies out there my center diff on my 92 is having issues. namely the diff lock actuator motor will not engage. I have gone through the test procedures in the fsm for the center differential lock control reray( thats what is says in the book at least) the relay the switch and the motor are all acting normally. yet it will still not engage. Now before I lower the transfer to try and diagnose this I had an idea. why would I not be able to hook a reversing polarity toggle switch to directly to the motor. the motor works fine. I beleive I just have a short in the wiring loom from the control realy uner the kcik panel to the actual motor. I drew up a little diagram of hwat I wsa thinking and found a toggle that is spring loaded so I can energize one way and hold it in the up position and then in the down position it will switch the polarity of the switch output.
other than it not being done right and bothering me what is the potential problems with this??
Dave

 

[Scamper]

If you belive you have a short in the wiring between the switch and the transfer, then the "test" for the motor would be to apply power directly to the motor at the transfer after the normal wiring has been disconnected. If you apply power to the motor while the standard wiring is still connected, and that wiring is shorted, you will simply be feeding power into the short and causing problems (though the motor may operate).

Reversing polarity on a DC motor usually achieves nothing more than the opposite of what it normally would do (maybe that's what you want here?).

After rereading your post...are you suggesting this all as a permanent fix? If so, I'd look elsewhere. If the short is still there and you provide it with power, you're just making a problem. Maybe a big problem.

Tom

 

[PHAEDRUS]

Sorry tom I guess I was not very clear,
the motor is a two strand dc powered motor. reverse the polarity of input to the motor and the motor reverses rotation. the motor normally engages for 2-4 seconds before power is stopped.
I know the motor works when power is applied directly to it. in both directions.
the question is I guess two part. does anyone know of any thing in this circuit wich is not included in the fsm??
if not, yeah I have a reversing polarity switchthat I can patch in outside of the normal wiring. unless someone can tell me what the output pin numbers are for the relay to the actual motor. I can not think of any other way to repair this without completely tearing hte wiring loom apart and re running every strand back to the transfer from the relay.
the stop gap solution is to bypass the trans control relay and connect swithced power directly to the motor.
I know that having engaged with a direct hook up form a battery the motor will engage and the cdl will engage and the dash light will turn on from past experiments. just curious if anyone knows this wiring diagrim better than what is shown in the fsm.
Dave

 

[RavenTai]

DO NOT send unregulated 12v directly into the motor, you will strech the spring (speaking from experience here on a friends 80 axle)

the limit switches in the actuator does not cut off motor power, the limit switches tell the relay to cut off motor power, without the limit switches the motor will overdrive until it stalls against the spring, and possibly over time cause other damage,

my friend put an 80 axle in a buggy , (very similar actuator to the CDL) having no stock harness or ecu he got an after market harness and switch it routes motor current through the limit switches witch I am not fond of because the limit switches are only made to handle relay coil current not full motor current but that is still better than unregulated power to the motor

 

[PHAEDRUS]

raven,
the plan was to use the toggle swithc and coutn to three, this would be the input after it was dropped through a 10amp fuse. I am not an electrical genius her but we are talking aobut short term usage of the switch sending power to the motor.
now witch limit switch are you talking about?? teh one in the kick panel relay?? the actual switch in the dash?? I respect your experience so am looking for some insight.
Dave

 

[RavenTai]

the actuator has limit switches inside, it is a flat metal disk with 3 sliding contacts, they open when the disk has gotten to the right spot either locked or unloacked, the relay box senses this and cuts motor power,

wiring the motor directly without the relay module and limit switches to protect the actuator even if only for 3 seconds will allow the motor to over travel and stretch the spring, the motor moves very quickly there is no way for you to manually cut power at the right spot with a switch

take a look at this starting on page 70 for a better description, this is for a 96 LX but I would think the 92 locker is similar if not identical

 

[PHAEDRUS]

Thanks for the link,
mine is a 92 so it is a HF2A. I read the entire section in the fsm and so no mention of the limit spring. but as per c dan the motor that moves the gear is identical from 91 through 97. I am kind of at a loss here. the pages you linked me too are not included in the fsm for the 92. there is no mention at all of the limit switch. hmmmmmmmm
I just want to get this figured out so I can abuse my truck next weekend.
Dave

 

[RavenTai]

That info is not in my 96 LX FSM either, that is from the New car features manual (highly recommended) , it gives detailed descriptions of the components and familiarizes you to the vehicle systems, the limit switches are also described in the EWD

according to Toyota the actuator is not suppose to be serviced only replaced if found bad, Dan cannot even get us parts for them, only the whole assembly ($$$) that is why the FSM does not discuss its innards,

 

[Beowulf]

>> that is from the New car features manual (highly recommended) <<

Wow! I gotta have one of those manuals for my '97. You dl'd that from the fee web site?

-B-

 

[RavenTai]

yep , $10 and 12 hours work for 135MB of .pdf's between 8 manuals and some other misc data, the NCF is a really great manual its gives you the why's not just the how's, when I first got my FSM I was bummed, it is did not have what I would call “description and operation” parts that I was used to in other FSM's turns it all that info was broken out into in the NCF,

I also have the paper version that I got from Toyota material distribution, since yours is a LC CDan can get you the paper version if you want both

The electronic version is quicker to navigate but for some things harder to work with, I like having both,