4WD Indicator Light & Wiring

[rich weyand]

My 4WD indicator never worked.  Working underneath the truck, I noticed a 2-wire connector (BLK and WHT) hanging down from the xfer case shifter lever hole.  I am assuming this is the 4WD indicator lamp switch connector.  Wiring colors match the wiring diagram for it.  So some questions.

Where the heck does this plug in?

Which bulb on the dash lights when this is operating properly?

If I had ever seen it work, it would be different, but I didn't even know it had one.

[Jason S]

Going off of memory (rapidly failing due to 3 small children)... 

The indicator would be in one of the windows of either the speedometer or fuel gauge. I don't recall if it indicates 4WD or Lock...  I believe the switch is on the "Lock" lever of the 203 shifter... 

I may be completely wrong and, if so, hopefully someone will correct me.

[Irish_Alley]

wish i could help but i cant i know i have the switch too but never needed it. due to the fact that if im driving and i cant feel the difference between 4wd and 2wd i prob should be driving. but it would be nice to know, thats why im replying now

[rich weyand]

Well, having a 12" long steel bar with a big knob on it sticking up out of the floor, whose position indicates whether you are in 4WD or not, is a pretty good indicator, but if there is one on the dash, wth, it might as well work.

[Irish_Alley]

yeah im with you lol

[rich weyand]

Yeah, it's on the LOC lever of the shifter mech.  Went over and searched on the 4WD section.  (Duh.)

[rich weyand]

OK, I found out that the 4WD indicator switch was disconnected on my 78 K-10, and I found the bulb socket hanging under the dash.

Can anyone tell me which position on the dash this bulb socket goes in?

[Boone83K10]

My 4WD indicator never worked.  Working underneath the truck, I noticed a 2-wire connector (BLK and WHT) hanging down from the xfer case shifter lever hole.  I am assuming this is the 4WD indicator lamp switch connector.  Wiring colors match the wiring diagram for it.  So some questions.

Where the heck does this plug in?

Which bulb on the dash lights when this is operating properly?

If I had ever seen it work, it would be different, but I didn't even know it had one.

on top of the transfer case, there should be a plug like this.


the bulb for the instrument cluster goes here

[rich weyand]

A little update here.

Like I said, the 4 Wheel Lock indicator never worked on my NP203.  Switch was busted, not connected, socket out of the dash, and no bulb.

I had to take the dash apart to replace the fuel gauge resistor anyway, so I replaced bulbs all around, put one in the 4 Wheel Lock indicator socket, and mounted the socket in the dash.

As for the switch, I looked up the GM part number and found several -- for $100 a pop.  Ran a cross-reference and it is the same switch used on the 1969 Camaro cowl induction.  It is the throttle arm switch that runs the servo motor that opens the cowl induction door.

Searched some more on "1969 Camaro cowl induction throttle arm switch" and found a reproduction switch and the little metal clip that it mounts in for $25 the set.

Now installed and I have a 4 Wheel Lock indicator on the dash!

[Irish_Alley]

lol $100 i think i would of been ok with no dash light but $25 good deal.

[Jason S]

Ran a cross-reference and it is the same switch used on the 1969 Camaro cowl induction.  It is the throttle arm switch that runs the servo motor that opens the cowl induction door.
Now installed and I have a 4 Wheel Lock indicator on the dash!

Good deal on both issues!

[80Chevy4x4]

I am gonna have to look at my truck...i have the light on the dash...i bet the moron that replaced my transmission didn't plug it in.