Which center difflock connector corrodes??

[IdahoDoug]

Anyone remember which connector has been discovered to impact the center diff locking operation? Someone here found a connector that was in a very tough location (atop the center diff/tranny?) that had become corroded and made getting the proper lights in the dash to light up.

My system is working correctly as far as the mechanics go (center diff is locking) but the ABS off light is not lighting, nor is the center diff light when I go into low range. The low range position switch is operating (current passes through when locked, does not when unlocked), but something else is amiss. A thank-you to ScottM here (my brother - heh) for spending a half hour on speaker phones reading his FSM to get this far. My '93 FSM does not have anything on the diff locks since it was the first year.

Anyone?

DougM

 

[landtoy80]

My center diff was not lighting up the diff lock light nor the ABS light.
Some how after a month or so it came back on.
I hope this helps

 

[RavenTai]

If the actuator is moving with transfer High<->Low then the Low 4 switch is good, take a look at the CDL indicator switch, from the other thread I gather that the front and rear lockers are not working? The diff lock Ecu watches the CDL indicator switch and will not allow them to operate until the CDL is locked, that further incriminates the CDL indicator switch

Never heard about the corroded connector, but have read about switches going bad some have successfully cleaned them and got them working again

This is where the CDL indicator switch lives:

 

[RavenTai]

link to related post: https://forum.ih8mud.com/showthread.php?t=20173

 

[scottm]

Tried to attach the schematic, couldn't shrink it enough and still read it. I just e-mailed it to you. If C2, center diff lock indicator switch is passing current, the light should come on if the truck is powered, regardless of anything else you do. I suspect connector EC1 near the starter.

Kurt, did your front/rear diffs lock when the light wasn't working?

 

[landtoy80]

The pic of the t-case jogged my small brain

When I had the same problem, I got one of my Position Switchs (from my old t-case) and plugged it into the L4 wireing harness from the t-case. I then with the key "on" motor off, pushed the switch (its a ball with a spring switch) and had the wife look at the dash. The ABS and CDL lights came on. I think the ball must of been stuck somehow (don't know why as it was only a year old new t-case).

Somehow you need to remove the switch (don't know if you can do it without removing the t-case) and push the ball to test the switch.

Note I don't remember if the switch lights up the light when the ball is pushed or at rest. I would put $$$ on the dash lights up when the ball is pushed.

You might be able to remove the switch from the rear or front diff lock or the other switch on the t-case if you can get to it.

scottm
The front diff didn't lock untill I pushed the ball of the switch. When I released the ball switch the front and center diff lights and abs turned off.
THe rear would lock and unlock all day long with the ABS and CDL light on, I have the Downey Cable Locker
I believe that the front and rear diff's wont lock untill the CDL/ABS lights are on, right???

 

[IdahoDoug]

Raven/Kurt/Scott,

Thanks. I tried a few different searches, then one with a generic approach that got me 9 pages of results, which I sifted through all evening. Turns out GregB had the exact symptoms on the same year rig and it was indeed the center difflock INDICATOR switch. I was messing about with the 2 switches on the rear of the center diff, not aware there was one on the front. So, I'll pull it and see if I can clean it like Greg did.

DougM

 

[Big_Moose]

Doug

Another method is to remove the washer between indicator switch & housing, allowing greater contact / pressure applied against the ballbearing.

Here is the attached CDL diagram..........

Joe

 

[landtoy80]

I looked at my switches from the old t-case and the two switches are not the same. The rear diff lock switch still might work??? and its easier to get to that the one on the t-case.

 

[landtoy80]

I tested my switch and its has 2 prongs on it. I checked for continunity (sp?)and when I push the ball up, the circuit is closed (it lets current flow) so you should be short the plug out and the light should come on (not responsable for any damage if you try this at home). Make sure you have the right terminal when you do this.

 

[IdahoDoug]

Thanks to all of you guys. What tipped me off was a thread where GregB had the same symptoms and was referred to a tech fix on the Slee site. This was written by Seto and I pulled the switch, cleaned it in 2 minutes, slapped 'er back in and all is working again. Though the tech fix recommended replacing it, I couldn't see how this simple and very heavily made switch could go "bad". So I became the second to simply clean it up. I used brake cleaner, then air to dry as much of this out. Then WD40 on the connector and dried this. Before putting the switch back in, I soaked it in gear oil to get it deeply into the switch again as it is on the top of the center diff case and may not get immersed for a while in gear oil. This was simply to be sure it's well lubed and protected from rust.

Regards to all

DougM

 

[Rookie2]

Doug,

I take it you were able to get to the switch on top of the T-case withoue removing the T-case as mentioned above (I think?)?


R2

 

[IdahoDoug]

Not only was I able to get to it, it was the easiest of them all. It's the one labeled in Post #3 above and simple to access.

DougM