Chevy 88-98 4x4 Actuator

Alright folks, I'm about 6 minutes away from burning my k1500 to the ground and buying an electric car.

I have been having problems with the thermal linear actuator for the front diff on my 92 k1500. My transfer case engages the front driveshaft no problem. When the vehicle is cold, the thermal actuator engages the front diff no problem. When the vehicle is warm (operating temp) the thermal actuator no longer engages the front diff. The fuse panel shows power  on the 4wd fuse, and the fuse is good.

Today I installed a new thermal actuator (upon the advice of my mechanic). NO change in the problem and I am out $120. I cannot afford a "posi-lok" cable, nor can I afford the drop in MPG by putting in a solid bar, but i need my damn 4x4 becasue duck hunting starts soon.

I used a test light an and found that there was no power going to the new actuator with the t-case in 4wd.  

What I need to know is some further details to the location  of relay's and switches in this system as I belive i have a heat induced electrical short somehwhere. I imagine there must be a wiring harness from the t-case to tell the front diff to engage, but i have yet to find it.

The internet seems devoid of any info. HELP ME!!!!!     

I had a thought in the last 1/2 hour (rare occurrence). Does anyone see a problem with me running the new actuator off a keyed 12V source with a toggle switch in the dash??? (with an in-line 25amp fuse as well). This would allow 2 low as well! Plus the indicator light on the t-case would function the same, preventing me from leaving the front diff engaged in 2HI.

Comments/Concerns?

Well i went ahead and did it, and it works amazing!

I would like to claim to be the first try this, but someone must have done this before.

It works perfect so far, cold, havent had a chance to bring the  truck up to temp and try it (which was alot of the prob before).

I'll see if this is the solution. And i get 2Lo out of the deal!

Good idea! I don't know of any one that has bypassed the electrical side of the actuator. If it keeps failing on you, I built a "copy" of the posi-loc system for less than $50. The most expensive part was the locking cable push-pull cable (about $35 from O'Reilly or Napa Auto parts) the rest was common odds and ends from the hardware store.

I was gonna do that too (build a copy of posi-lok) but the open end of the cable would probably disagree with the copius amounts of salt the province isnsists on rotting my truck with all in the name of traction (for yuppies who wont buy winter tires).

I am lovin that switch in my dash now. I am impressed with my own ingenuity...had been in a "brain slump" for quite some time now...

I used a piece of 5/16" smooth rod, threaded with a clevis on one end to pass through  the axle housing to the central axle disconnect. I used parts of the original actuator housing, and some washers, grommets, and O-rings to seal it up, and it's been working great for 3 years.  I might post a picture, but I'm not sure that the Posi-lock guys would appreciate it...  

I could see why they might not like it!. Sounds like you built a better unit anyhow.

So far my switch is operating problem free. I do have some concerns on how much juice that the actuator may be drawing from IGN+ source. I am considering rewiring and using a proper relay.

Any ideas on how many amps that the actuator might draw?

Hey my name is dennis and i've got a 92 with 330,000 on her and have the EXACT SAME D*MN PROBLEM !!! I took the actuator out and hooked it up too the battery to test.  It worked, but slow, real slow.  And that thing got so hot even when held to power for several seconds that I almost couldnt hold it.  So what i'm thinking from what u put down, is that the slow means its workin, right? My question is did u test yours, and if so, did it move slow?  And does yours get real hot when engaged for a long time?  I'm thinking if i wire it up to 12v somewheres that its gonna fry something.  Let me know.  I can use all the help i can get. Thanks  bignmuddy  

Sorry i forgot that thee ol battery has  700 some amps and the actuator probably doesnt need that to engage.(that would explain the so hot i cant touch thing.)   Do u guys no what amps that takes to engage?  Well i'm makeing some progress, i think.....thanks again  

is it the vacuum switch on top of the transfer case? this is the only other thing i would think!!!!  
asphalt=another example of wasteful government spending

The actuator is only going to draw the amount of current it needs. To find out what the current draw is you can either connect an ammeter inline and measure it, or start stepping down in fuse size until one blows.
And you defenitely want to rewire using a relay.  
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seen in FOUR WHEELER magazine July 2006 and OFF-ROAD magazine Feb 2007

'84 4Runner SR5 -
ARBed 5.29s F&R, 4.7 & 2.28 t-cases, 2" drive train lift, AP hy-steer, BudBuilt x-member/skidplate, 36" TSLs, 30 spl Longs, Chevys, rears up front, winch, yada yada ...

'80 something Toy P/U -
Buick 231 V6, Holley 4 bbl, Weiand intake, Downey headers, TH350 L/U w/700R4 low gearset, dual tanks & batterys ...

89 4Runner SR5 -

hey was just wondering, i have the same problem with my 92 1500,i took out the old acuator, cut the end of  got a rod ,thresded one end so it would slide thru the opening but was wondering if i have to cover the other end so it wont leak. any ideas would greatly help thank you  

HI

I have an 88'. When I put it in 4WD the actuator is slow coming out, but when it is fully extended I can push it back in with my finger, I went and picked another one up at a junk yard and I can also push it with my finger. I don't know allot about the actuators. I wish I had a solid axle again.. Can anyone give any advice?

Thanks  

hey guys...i have a 98 k1500 with the 4.3.  i am having the same problem with the actuator not engaging.  took the actuator out of the front diff and hooked the harness back up and put it in 4wd and nothing happened. (tested the harness with a volt meter and there is power goin to it) then we bench tested it with a battery and still nothing.  the only difference im having is when im driving at 55mph in 2wd there is a "clicking" noise coming from the front diff area. when the truck is in 4wd there isnt any noise.  so just to get by until i could work on it i took the front drive shaft out and the noise isnt there any more.  The CV shafts are good, new U-joints and there is normal play in the yoke on the front diff.  I see that the posts are from about a year ago so hopefully someone will see that i posted this.  If i could get any feed back it would be awesome!!  THANKS!  

I am very curious on how you wired it up so the light came on please reply asap as it is snowy here and need my 4x4 working i know this post has been dead but its about the only helpful info i have found