Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

4-wheel light question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Peeetah, Jan 10, 2001.

  1. Peeetah

    Peeetah Registered Member

    Joined:
    Jul 3, 2000
    Posts:
    97
    Likes Received:
    0
    Location:
    Mt. View, CA
    When I used to put my truck in 4 wheel drive a yellow light would come on under my speedo that said 4-Wheel. It no longer lights up when I am in 4-hi / 4- low. I do not think it is the bulb because all the other bulbs are working. I am wondering if their is a connection on the tranfercase or anything ealse that sends this signal that might have come loose.
     
  2. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    I don't follow your logic. If a light bulb burns out in your house, do you assume it to be good, because all the other light bulbs in the house are still working? The bulb may have just burned out.

    The wiring is pretty simple. My t-case is a 1980 NP205 and it has a switch that completes the circuit for the light when the case is shifted into 4WD. Look around under there to see if the plug got yanked off the switch.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  3. militaryblazer

    militaryblazer 1/2 ton status

    Joined:
    Nov 14, 2000
    Posts:
    235
    Likes Received:
    0
    Location:
    Azle, Tx
    My 4wd light doesn't work but that is because I cut the two wires that ran to the t-case when I had my bedliner sprayed cause they wen't across the floor!

    [​IMG]See more--&gt;<A target="_blank" HREF=http://www.geocities.com/m1009_86>http://www.geocities.com/m1009_86</A>
     
  4. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    I'd like to figure this out too 'cause mine does the same thing. I ran out cross this when i was tryin out my new driveshaft after I got the truck. The bulb in mine is fine, I had the whole cluster out while changing bulbs. Its also plugged into my 208C, this is really bugging me. He peetah, its really easy to check your bulb. Take off the vent tube above the pedals is you have A/C and reach your hand behind the speedometer, you should feel two bulb holders side by side at the bottom of them. The one with the wires comming out of the back is for the four wheel drive. I can't even get my shifter knob off of my transfer case, man a 245 bench press and I can't even get 'er off (brag [​IMG].)

    (Please direct all hate mail to "Blazer_Boy" because I don't think "BlazerBoy" would appreciate it [​IMG])
     
  5. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Break out the ol' voltmeter and see if the 12 volts is going where it ought to go. You can also ohm out the switch to see if it closes when you shift the t-case to a 4WD position.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  6. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    I think its probably the switch unit on the T-Case. I know there's two contacts comming out of the case. How do go about testing them? If the switch is toast can I just unbolt it and drop in a new one? Thanks [​IMG]

    (Please direct all hate mail to "Blazer_Boy" because I don't think "BlazerBoy" would appreciate it [​IMG])
     
  7. BlazerGuy

    BlazerGuy 3/4 ton status

    Joined:
    Apr 20, 2000
    Posts:
    9,206
    Likes Received:
    0
    Location:
    abcde
    Why do you need it? Is it really that important to go through all that trouble to get it working again?

    [​IMG]
     
  8. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    Yup, life isnt easy when you're a perfectionist. You lose sleep over the littlest things, well not really but it bugs me. I couldnt stand it when half my bulbs were burnt in the dash and my door light switch didnt work, does now [​IMG]

    (Please direct all hate mail to "Blazer_Boy" because I don't think "BlazerBoy" would appreciate it [​IMG])
     
  9. Peeetah

    Peeetah Registered Member

    Joined:
    Jul 3, 2000
    Posts:
    97
    Likes Received:
    0
    Location:
    Mt. View, CA
    Right

    Your right Harry my logic was very flawed. What can I say. I just like to see the pretty light come on when I am in 4-wheel drive. I love the fact that my Jimmy has all four gauges and a Tach and speedo. Do I really need them no idiot lights would suffice but, they give me something to look at at stop lights.
     
  10. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Blazer_Boy, do you have a volt/ohm meter? If so, unplug the wires from the switch, then connect the meter to the two pins on the switch. Set the meter to read ohms. In 2WD, the switch should be open (infinite ohms). In 4WD, the switch should have 0 ohms. If it still reads open in 4WD, then the switch is dead. And yes, it just unscrews and you screw the new one in it's place. I'd put just a dab of RTV on the threads first, to keep it from leaking.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>
     
  11. CV202

    CV202 1/2 ton status

    Joined:
    Nov 14, 2000
    Posts:
    454
    Likes Received:
    0
    Location:
    Kingfield, ME
    It may sound dumb, but is the other end plugged into the side of the T-case?? It fell off on mine and *Bink* the light goes out. Start simple before you Frig with meters and rip the dash apart. If you're like me, you just end up making more things to fix! :)

    Why do people keep calling it a Bronco!!!!!
     
  12. Blazer_Boy

    Blazer_Boy 1/2 ton status

    Joined:
    Dec 16, 2000
    Posts:
    1,669
    Likes Received:
    0
    Location:
    Sioux City, IA, USA
    Oh ya I've been under there to check the connection long ago. If the damn snow would ever leave here I'm gonna crawl under and trying cleaning the connections. Of course knowing my luck the switch will be toast, damn I need an ohm meter.

    (Please direct all hate mail to "Blazer_Boy" because I don't think "BlazerBoy" would appreciate it [​IMG])
     
  13. River

    River 1/2 ton status

    Joined:
    May 8, 2000
    Posts:
    121
    Likes Received:
    0
    Location:
    Amstelveen, Netherlands
    In other posts about this problem i read that the switch is not only for the 4x4 light it also prevents the transmission from going into lock-up.

    greetings from Amsterdam,

    River `90 K5, 350, TH700R4, NP241, "33, 3.08, 10 bolt F, 10 Bolt R(GOV-Lock)
     
  14. Wheels

    Wheels 1/2 ton status

    Joined:
    Aug 18, 2000
    Posts:
    638
    Likes Received:
    0
    Location:
    Native Floridian living in Oklahoma, USA
    The 4-Wheel light runs on it's own circuit and is powered off the fuse box (comes on regardless of the dash lights when selected). The bulb could be burnt out, switch bad, or the connector disconnected. There's not much to this circuit. Mine was really dim and could only been seen at night. When I pulled out the dash, the bulb socket had fallen out on the back of the dash. During the rebuild, I ran mine out the fire wall with the speedo cable and down to the switch.
     

Share This Page