Still no 4WD after new actuator and harness

[fastcat800]

I put in a new GM gear motor actuator and spacer and connected the brown wire off the new harness to the brown wire on the switch on the top of the transfer case (per the parts guys instructions as there were none with the new harness)and it still does not engage in 4WD. What's next, change the switch?

[20050627|3|008327|000043|65.183.99.20]

Crawl under with a meter and see if you get power to the brown wire on the T/C.

I went about 5 months (through winter) after the change with no 4wd. Turned out I didn't put the switch on the transfer case back on fully.

The new unit is a really simple system. So I suspect you have a power problem somewhere.

[fastcat800]

I will check for power at the brown wire when in 4WD tomorrow. I know the connector is on all the way because I heard it snap when I put it on and it was locked in. If I have no power on the brown wire then do I assume the switch needs replacing? I know the TC is working as the driveshaft to the front differential is turning. What is the switch that is on the top of the TC for? Is it just sending a signal out the brown wire when in 4WD? What wire is the power in, the blue or green? I would guess it was the blue and the green is ground. I would like to check for power in, if there is non coming out before replacing the switch.

[rjschoolcraft]

I had problems with the connector at the T-case switch making intermittent or no contact. Squeezed it with pliers...good as new.

[20050627|3|008327|000043|65.183.99.20]

Not sure of the wiring except that the brown is powered when in 4wd.

Do your shift lights work?

[fastcat800]

No, the lights do not work. The connector that goes to the front axel is riped off and has three wires hanging there. The other half of the connector is still there just hanging. Been that way since I bought the truck. Could this be related? I have to get it fixed within the next few hours or drive my old van that has posi as I am going to the lake for the weekend. I guess I could fill the box with fire wood so I can get enough traction to get the boat up the ramp.

[rjschoolcraft]

Originally posted by Dave Schumacher:
The connector that goes to the front axel is riped off and has three wires hanging there. The other half of the connector is still there just hanging. Been that way since I bought the truck. Could this be related? You bet!

[BobND]

The wires at the front axle, other than those to the actuator, operate the 4 X 4 light when the axle disconnect actuates and hits the switch they are connected to, but will NOT affect the actual engagement of the front axle disconnect actuator.

The brown wire at the TC will have power as long as the ignition is "ON", whether or not the TC is in 4 X 4. It is fed through a Fuse, I believe, labelled 4 X 4. It IS NOT switched by shifting the TC.

Have someone shift the TC in and out of 4 X 4, (key "on", engine "OFF"), while you listen up front. If the actuator motor is functioning, you will be able to hear it.

Have you verified you do not have a mechanical problem... transfer case, front drive shaft spline, front ring and pinion, or differential problem, or a stripped CV shaft?

[rjschoolcraft]

There are two sets of wires. If the wires that connect to the actuator are bad, of course that will affect the operation. My assumption when I read the post.

The other set of wires is connected to a switch that provides feedback in the form of a light to inform the operator that the 4wd is engaged. If these are bad, no, the operation of the unit will not be affected.

However, there is power on one of those wires with the key on. If this wire shorts against a ground, it could blow a fuse which will affect engagement of the front axle.

Repair those wires. I still say that you should verify contact at the transfer case switch. Without it, nothing in the front end works.

[fastcat800]

I don't believe there is a mech. problem. The kid looked last night at the front drive shaft and it turns. I have used 4WD all summer long to pull my boat out of the lake. About 50ft, once or twice a week. It made no noise this last time like something broke, it just started to spin the RR tire and I always ease into the pull out. Why does the brown wire have to have to be hooked to power from the TC switch. There was already power there to run the thermal actuator. Trying to figure out how this works so I can trouble shoot it. The connector missing is for the light and is not able to short out so should have no effect on engagement from what you guys have said. I am going to check to see if I hear the actuator motor running before I leave. I will be shocked if it is working. No time to do any more now.

[BobND]

The thermal actuator only needed 2 wires, switched hot, and ground, because it was power engaged by it's heater, and disengaged when it's heater was shut of, and the actuator cooled.

The new actuator is a gear motor, and needs switched ignition power to the brown wire, plus the original switched "actuate" power, plus a ground.

It has internal "logic", and limit switches. It is power apply (extend), and power disengage (retract).

So, you need power to the brown wire, a functioning ground wire, and the wire that operated the original actuator, which will switch "on" and "off" with the movement of the TC shifter.

I don't remember the colors of the other 2 wires, but:

4 X 4 engaged... brown wire "hot", one other wire "hot", and one wire "grounded".

4 X 4 disengaged... brown wire "hot", one other wire "not powered", and one wire grounded.

[fastcat800]

What a dope I am! It was the fuse! Works great, you can hear the actutor run when you turn the key on if it's in 4WD. Thanks for the help guys. Next week I am going to fix the connector for the indicator light. I suppose I will have to go to the junk yard to get half a connector.

[BobND]

What was the fuse actually labelled?

[fastcat800]

The fuse was labeled 4WD.