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Discussion Starter #1
Title says it all. The harness I got only had the paper that said be sure to include the spacer in the front diff before the actuator. I have no clue where the wire is supposed to go? The dealer said it goes to the brown wire on my Transfer case but there is a couple of different plugs so if anyone could lead me to the right one I would really appreciate it!
Thanks,
Jason
 

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What truck are you working on?

BTW - a search would have turned up the answer....
 

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Discussion Starter #3
It's a 94 3500 Heavy Duty.
I did do a search and the only thread I found was locked and it only said to wire the brown wire to "hot". There is a "hot" to the light but I was told that is not it.
I just want to be sure. What should I have searched for besides 4wd actuator?
 

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I need to know this info to, I have a 93 k3500 that has a manual actuator. I'm thinking I need one out of a 96ish, that has a two wire harness which should just be 12v on when you want engauged.
 

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Discussion Starter #5
I was told there is supposed to have been a schematic in the box with the harness but the only paper in my box stated I had to put the spacer in before installing the newer actuator. No schematic though.
 

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When I replace my actuator I ran the Brown to the power bank under the hood. Sorry I don't know what the "power Bank" is called, but it's on the passenger side with a black cover on it, once you remove the cover the there are a number of studs there. I put a ring terminal on the brown wire, removed the nut off the stud closest to the passenger side fender, put the ring terminal on put nut back on and tightened it down.

I have done this twice once on my 94’ and once on other 94’ over a year ago with no problems to date.
 

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Discussion Starter #7
So the brown wire just needs 12v at all times or is it supposed to be a switched 12v when you engage 4wd?
 

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Mine is all the time 12v
 

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Discussion Starter #9
Thank you very much 94Blazer!
 

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It is supposed to be 12v switched/fused. The brown wire they are talking aboot is the middle wire on the tranfercase engagement switch located on top of the transfercase above where the front driveshaft comes out of the transfercase.
 

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Discussion Starter #11
roblrobl,
Thank you very much. I think I hit the wrong brown wire from what you described but it works so far. I tapped into the brown wire that looks like it starts as a red wire that goes into a fueseable link and then turns into a brown wire on the rear end (the brown wire actually goes into the bottom of the TC torwards the rear where the drive shaft going to the rear diff is). From what I could tell going into the fuseable link it was only hot (12v) when the lever was pulled into 4wd. So I tapped into it and everything is working good so far. I have tried it 3 times since the install and within 100 miles and it has worked every time.
Thanks for all the help guys,
 

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You need 12V+ whenever the key is on, otherwise it will not unlock the front axle. If you tapped into the brown wire that is only 12V+ when in 4X4, the front axle will NEVER unlock.
 

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How would check if the front axle if locked or unlocked? I can tell you that my does not feel like the axle is locked when driving. Could jack the truck up, put it in gear, and see if the front wheels turn?
 

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Discussion Starter #14
You need 12V+ whenever the key is on, otherwise it will not unlock the front axle. If you tapped into the brown wire that is only 12V+ when in 4X4, the front axle will NEVER unlock.
Wow, thanks so much for posting this info. I am going to look into it today! If that is the case, I will probablly do what 6.5blazer did and go to the electrical center under the hood---its a lot easier to get to than on top of the TC.
Whats funny is that my light that says I am in 4wd comes on right after putting it into 4wd and it goes out just after taking it out of 4wd so I was assuming that it was unlocking? Does the light just go out when you move the selector to 2wd? I thouhgt as long as the front was locked in the light would be on?
 

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Discussion Starter #15
How would check if the front axle if locked or unlocked? I can tell you that my does not feel like the axle is locked when driving. Could jack the truck up, put it in gear, and see if the front wheels turn?
That is what I am thinking of doing---or else I'm gonna find a mud puddle and see if I get stuck in 2wd or not like I normally would. :D
 

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Whats funny is that my light that says I am in 4wd comes on right after putting it into 4wd and it goes out just after taking it out of 4wd so I was assuming that it was unlocking? Does the light just go out when you move the selector to 2wd? I thouhgt as long as the front was locked in the light would be on?
Yes mine does the something. Light on when in 4wd, light off when in 2wd.

I also just tested it in dirt.... 2wd only back wheel spinning and truck getting a little side ways, in 4wd tire barely spin and truck took off like a pro-stock car... OK maybe not like a pro-stock car but fast for a big Blazer. :D
 

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You need 12V+ whenever the key is on, otherwise it will not unlock the front axle. If you tapped into the brown wire that is only 12V+ when in 4X4, the front axle will NEVER unlock.
I am sorry but you are incorrect here. The main power feed for the front actuator comes from the original actuator power circuit. The switched power taken from the tranfercase is basically just the 4wd request. The ones that hook the power feed to 12v are the ones that will never unlock.
 

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Discussion Starter #18
I am sorry but you are incorrect here. The main power feed for the front actuator comes from the original actuator power circuit. The switched power taken from the tranfercase is basically just the 4wd request. The ones that hook the power feed to 12v are the ones that will never unlock.
So I am right having wired to switched 12v when I engage 4wd? I just figured the light wouldnt lie b/c it is turned on coming from the top of the front diff, like it has a sensor or switch in the front diff that turns the light on when the actuator is extended. I'll give it a test here in a bit just like Blazer did.

Thanks for all the help guys, I hope this helps someone else in the futre as well! The updated actuator is a HELL of a lot faster that the old style, thats for sure!
 

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I am sorry but you are incorrect here. The main power feed for the front actuator comes from the original actuator power circuit. The switched power taken from the tranfercase is basically just the 4wd request. The ones that hook the power feed to 12v are the ones that will never unlock.
The brown wire that you hook in is the power for the motor to work, if it doesn't have power it cannot move the actuator. The origanal thermal system only had power to the axle when 4X4 was selected. You took the power away and the thermal actuator would cool down and unlock. So the 2 wires that are already there are your ground, and the 4X4 trigger wire. There is no source of 12V+ to the front axle when in 2 wheel drive, that is what the brown wire is for. If you hook the brown wire to the 4X4 request wire, you will get 4 wheel drive, but the front axle will not dis-engage when you go back to 2 wheel drive. The transfer case will unlock and give you 2 wheel drive, but if you trey and turn the front drive shaft by hand you will find that the axle is still locked. So you are spinning all the drive train, even though it is not all locked together.

And the 4X4 indicator light get's it's power from the 4X4 switch on the old style system, so as soon as you pull it into 2 wheel drive the light goes out(wether or not the front axle dis-engages). But the light only has a ground when the front axle switch senses engagement. Get your test light out and check it out for yourself. Went through this same discussion last year on this forum(in steps the search feature).
 

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Oh crap. You're right! Man I feel like an idiot. Should never rely on memory,mine likes to play tricks on me.

The brown wire is indeed just a switched 12v feed. Sorry for the confusion I might have caused. I will shut up now...
 
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