92 2500 chevy 4x4

Have you checked fuse that feeds it?

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yes i have checked the fuse and i have power there and the fuse is good

According to the schematic, the front actuator always has power to it. All the switch does is add a ground to the circuit to allow it to work. It is wired directly from fuse to actuator and then the switch grounds it so you wil never see voltage at switch unless it is back feeding from actuator and switch is open. Do you follow me on this?

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i think so does the ecm have anything to do with the 4wd that and ive been thinking of going with a 4x4 posi lok kit

I am just getting 4X4 working this afternoon also. I pulled my plug at the transfer case and had no voltage which you don't have so I think it might be your 4WD of AC/ HTR fuse is blown. Does the heater work? I am sure you have the four engage in the cab and the key is on when you're checking the voltage. I had to R&R my actuator with a GM part, $184 for the old style. Doug

Correct. ALso on the pster wanting to go to posilock, consider this, starteing in 98 GM went to a servo control axle actuator that is VERY reliable and it can be retrofitted. The posi lock has exposed shift linkage that could become jammed with mud or snow and ice. I have 2000 K3500 SRW old style (not a silverado) and in 7 years of plowing snow it has not failed once even in extreme conditons and well below zero. THe older thremo style ones (88 to 97) are troublesome at times. Also they disengage when key is turned off but the new style servo ones remain engaged because they have to be powered in and out of engagement by servo motor in them.

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well i called my gm dealer and gave them my axle code and make and modle and they told me that 88-93 2500 HD trucks could not pe upgraded to the new style actuator so now i am realy thinking of the posi lok and ive talked to a few ppl that have and they realy like it and have had no problems but im stile parce to just pulling the lever if u could i would like to see the wiring diagram so if u would please send it to me thank u cuz ive checked everything and i cant figure it out

First, check for a blown fuse (A/C-HTR fuse)

2) With ignition switch in run position, check for battery voltage at the transfer case switch, terminal 1. If missing check for open wire.

3) With ignition switch in run position and 4WD control in 4WD engaged position, battery voltage should be present at terminal 2 of the transfer case switch. IF not replace transfer case switch.

4) With ignition switch in run position and 4WD control in 4WD engaged position:

Battery voltage should be present measuring between connector 3 and ground at front axle solenoid. (That should be the actuator.)

Battery voltage should be present at connector between 3 and 4. If not repair wiring. (4 must be the ground, and it's not switched!)

5) If step 4 is OK, disconnect solenoid harness, remove solenoid from axle. Plug solenoid into harness. (Ignition switch in run position and 4WD control in 4WD engaged) Solenoid plunger should extend within several seconds. If not replace.

6) Repair as necessary. :)

If I were you, I'd use a test lamp and not a digital meter.

Good hunting,

Al

Strange because my GM dealer manual clearly shows that it is. (it is from GM SI computer manuals) ALso It is strange that dealers says that it will not retrofit because it should bolt right it. You do have to add a extra control wire and and a SPST switch if current switch is SPST because the old style has only one power wire to heat and expand the gas "pil" to engage axle while the servor one has to be powered into engagement by one wire and powered out by a second wire (hence the need for extra wire and possible switch upgrade) Have dealler pull a 88 to 93 actuator and a 98 and later one and see how they mount/bolt up and if it is the same, a little wiring will make it all happen even if you want to install a manual switch to lock and unlock it. I shy away from posilock because like I said eariler, the shift linkage down there is fully exposed to elements.

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a Typo, it should say "a SPDT switch if current swwitch is SPST" (SPDT means single pole double throw and SPST means single pole single throw)

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