4 x 4 light flickering when engaged.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

beachsuburban

Member
Joined
Apr 11, 2017
Posts
31
Reaction score
5
Location
De
First Name
J
Truck Year
89
Truck Model
v2500
Engine Size
5.7
Any ideas? I am thinking the switch but not sure where it is. Any help would be great. Thanks
 

EvilGenius

Full Access Member
Joined
May 12, 2016
Posts
205
Reaction score
159
Location
Metro Detroit
First Name
Darien
Truck Year
1983
Truck Model
K10
Engine Size
350
The transfer case switch is located on the transfer case. It sits on the front half of the case right above the shifter linkage. It is pretty robust and I'm not sure of a failure mode off-hand that would cause the switch itself to cause intermittent flickering of the indicator light.

My guess at your issue is the gauge cluster itself. Based on my own experience with the gauges in these trucks, the bulb sockets do not make very good contact. I would start by pulling the gauge cluster and swapping the 4x4 indicator bulb with another one you know is rock solid to see if the flickering follows the bulb.

The other option is a bad ground. The 4x4 indicator does have it's own ground wire, but it just connects to the ground junction block on the parking brake bracket. If this ground location is bad it would have other cascading effects most likely. I did a write-up a while ago on how I rigged up my light to work here . Not sure how close this was to factory wiring, but I did attempt to make it work with factory equipment.
 

beachsuburban

Member
Joined
Apr 11, 2017
Posts
31
Reaction score
5
Location
De
First Name
J
Truck Year
89
Truck Model
v2500
Engine Size
5.7
Wow that is some great info! So it seems like its in the shifter. I have been driving the truck for years and just the other day when I was in 4 it came on and it was so awesome. Now I can get the flicker when moving the shifter around, getting a good light response when going between 4 hi and 4 lo.
 

beachsuburban

Member
Joined
Apr 11, 2017
Posts
31
Reaction score
5
Location
De
First Name
J
Truck Year
89
Truck Model
v2500
Engine Size
5.7
Any more ideas? If its flickers when moving the shifter around wouldn't that mean it is in the transfer case switch? When it first happened it was flickering when driving in 4, now I can get it to come on when moving the shifter around, if i find a good spot it will stay on but goes off when the shifter moves back to where it wants to be on its own.
 

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
326
Reaction score
412
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
I would start by looking at the switch & making sure the connection is good. The switch provides path to ground.
What does the 4wd lever lamp do? it uses the same ground. (The 4wd lever lamp needs the headlights/parking lights on to work. If it doesn't come on- bulb might be bad.)
 

Attachments

  • 89_4wd.jpg
    89_4wd.jpg
    59 KB · Views: 25
Last edited:

Blue Ox

Turning Diesel Fuel Into Fun
Joined
Mar 27, 2018
Posts
5,253
Reaction score
12,180
Location
LI-NY
First Name
Derek
Truck Year
MCMLXXXV
Truck Model
K20HD
Engine Size
6.2L
I've had two of those switches fail. Haven't bothered replacing it again. Don't know if my experience is unique, but it hasn't been good.
 

Old Guy Bill

Full Access Member
Joined
Sep 10, 2023
Posts
445
Reaction score
1,373
Location
KY
First Name
Bill
Truck Year
1978
Truck Model
K20
Engine Size
400
It’s most likely a “ball detent” type of switch, it’s screwed into the case.
The shift lever part inside the case actuates the switch when in position.
Check the shift linkage at the TC, it may be sloppy there or you just need a new switch.
 

beachsuburban

Member
Joined
Apr 11, 2017
Posts
31
Reaction score
5
Location
De
First Name
J
Truck Year
89
Truck Model
v2500
Engine Size
5.7
Sounds like that is the place to start Bill. Thanks for sending me in that direction.
 

JBswth

Full Access Member
Joined
Jan 24, 2022
Posts
236
Reaction score
194
Location
Vallejo, California
First Name
James
Truck Year
1973
Truck Model
C25
Engine Size
292 cubic inches
Wow that is some great info! So it seems like its in the shifter. I have been driving the truck for years and just the other day when I was in 4 it came on and it was so awesome. Now I can get the flicker when moving the shifter around, getting a good light response when going between 4 hi and 4 lo.
Does the transfer case shifter have linkage? If so, perhaps that is not adjusted right. I remember the backup lights did not stay on in the 81 C10 that I had. The gearshift linkage was not adjusted correctly, so when you put it in Reverse, the lever didn't go as far up as it was supposed to. Adjusted the linkage per shop manual instructions fixed that problem and the problem of it sometimes popping out of 1st gear.

J. B.
 

Latest posts

Forum statistics

Threads
44,414
Posts
956,988
Members
36,738
Latest member
Tjreid
Top