Boy did I get lucky!
First it is a good thing I didn't touch the new one yet.
I called cdan and my unit is under warranty for another 15 days. I got it on Sep 16th 2009.
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Fixing the old one:
I understand what to do with the gear mechanism, I read enough about it and I already opened it last year. However, what exactly do I do with the electric motor? Say I am successful in opening the cover. Besides making sure the contacts are in the right place, what should I be doing in there?
The most common problem with the motor is the magnets coming off of the motor housing and sticking to the armature. Sometimes a bushing binds, in ether case there is danger of letting the magic smoke out of the motor.
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Also, there has to be a way to test the actual harness. If I give up on the old actuator, I can use the harness from it to see what the actuator sees from the harness. Other than that what will be a way to test the harness?
There is a test procedure in the FSM, has been posted in some of the other actuator threads. It has resistance readings for the motor and expected readings for the various connections.
I have an associated problem: 80 series LC diff lock ECU speed sensor bypass.
I'm not sure if the 1994 80 series has this speed sensor, but all my actuators are working fine. When testing the rear actuator engaged and won't come out. I then read on the www.yotatech.com forum that the speed sensor feed to the diff lock ecu is fed from the Speedo consul. My Speedo in the consul is fried. So, I would like to bypass this with a switch if possible.
My question in order to do this would be:
When the speed of the vehicle is below 8km/hr is the feed from the speedo sensor to the diff lock ECU grounded or send a positive feed or does the ECU sense pulse rates? If pulse rates, what can I use to simulate the pulse rates (perhaps a direct feed from the gearbox sensor, or a simple pulse circuit)
I want to bypass the sensor as my Speedo is burnt out so I can get the e lockers to disengage.
The diff lock ECU senses pulses from the speedo circuit inside the combination meter; this same signal is also used by the engine ECU and cruise control. How to simulate this signal isn't obvious because the EWD does not disclose the interior circuitry of the diff lock ECU. Some pulse rate must be required otherwise you would be able to unlock your rear actuator. And too high a pulse rate probably also prevents the actuator from functioning because the ECU would think the vehicle is moving too fast -- but that's just a guess. You need to get your hands on a multimeter that can read out frequency and then probe the circuit on a working vehicle. That will tell you the pulse frequency as a function of vehicle speed and you can design a simple pulse simulator circuit from there. My guess is that it's a square wave pulse, so a simple timer circuit using a 555 timer IC should do the trick once you determine what the pulse rate should be.
IIRC, the SPD signal is a pulse when moving, nothing when stopped. When the pulse is at a fast rate, interpreted to be ~5mph or faster, locking is prohibited. No pulse = stopped, so with that connection unplugged, the locker ECU always thinks the rig is stopped, lockers will work at anytime.
The speed signal is a pulsed, TTL type signal, and from what I can tell, it's about 1Hz per MPH. The signal is grounded when low, and floats when high (open collector).
BUTT, as Tools said, the diff lock ECU only uses this signal to PREVENT locking above 5mph.
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