94 K2500 no 4X4 engage

[a5150nut]

Checked for voltage and getting 12v but no continuity to ground. And no continuity between pins on accuator

1 2
0
0 3 pins on connector 1 12v when engaged 2&3 nothing 0's blank

1 2
4
5 3 pins on accuator no continuity between any pins

Pulled the accuator out and put in 4x4 but no response. This is the updated one not the thermal accuator.

What next to check?

Tried to diagram but when I save it drops spacing. Pins are spaced to each corner with middle pin centered if that makes sense.

[trbankii]

I wasn't aware there was an updated version other than the aftermarket cable actuator.

[Robyn]

Yessss, the later unit is a servo motor type that can be retro fitted in place of the Thermal Gizmo

The best thin to do is forget the electrical crap and install the cable unit.

The next time your out in the bush and the Snow is flying sideways you can rest assured that a simply pull/push will make the 4x4 work.

The electrical stuff is just too prone to failing, and it will fail when you really need it most.


Missy

[greatwhite]

My 98 is running on the original actuator from 98. Never given me a whit of trouble and I've had the truck in some pretty abusive conditions for undercarriage. Everything from totally immersed in water (and sitting) to plowing in door deep snow.

The only trouble it ever gave me was some poor solder joints on the in dash push button panel and shifting itself into full time 4x4. A quick touch of the soldering iron and all the trouble went away. Poor solder joints are a pretty common thing on GM electronics from this particular era.....anyone who's ever had to watch their wipers "spaz out" knows what I'm talking about...:rolleyes:

Everything is prone to failure though, even mechanical systems.

I'm not really picturing what you're saying with your diagram, but this might help you out a bit since your truck is an upgrade and not an OE installation:

http://www.getdieselpower.com/cars/actuator_upgrade/GM_TRUCK_4X4_ACTUATOR_UPGRADE.html

At least that will give you an idea of what you're dealing with in the upgrade kit vice an original installation. Maybe it will give you a few ideas on where and what to look at.

I'd try and fix what you got until it becomes obvious you're going to have to spend more to fix it than swap over to the posi-lok system.

Or spend the money if you prefer the pull the level and forget it convenience.

Personally, (and I never thought I would say this) I prefer the push button system. I'm an old lever puller from way back, but I would never go back on my (mainly) "on road" truck. I can drive around in winter with 2wd and getter better mpg. When I'm sitting at a slippery intersection I hit 4 hi and I'm gone with no fuss at all, leaving traffic far behind (even teh front drivers). I can hammer the throttle pretty hard and have minimal spin at any time in 4x4. Once I'm past the slippery stuff, another stab at the button and it's back in 2wd. It literally takes less than a second to shift in and out. Whether I'm moving of sitting still.

That's convenience I'm willing to pay for.

If I were driving a mainly off road truck, I wouldn't have IFS and I would either have manual hubs of full time.

I'll sneak out to the garage tomorrow and see what the diagram and trouble shooting looks like in my 98's FSM looks like.

If it gives pinout voltages and whatnot, I'll post 'em up.

It's just too damned cold and dark to go out tonight......;)