Instrument Cluster Connector - The 1947 - Present Chevrolet & GMC Truck Message Board Network

blukangoo · 04-28-2025, 12:56 PM

I found this connector on a bulb on the back of the instrument cluster, does anybody know what it is for? It is not connected to anything, it's just there.

too much stuff · 04-28-2025, 01:09 PM

That sends light up to your gear selector on the column with an auto trans.

HO455 · 04-28-2025, 01:10 PM

It is one of the dash lamps for the speedo or fuel guage. The line attached to it is a fiber optic cable that illuminates the gear selector on the steering column.

blukangoo · 04-28-2025, 02:00 PM

Well I'll be!

I didn't think they had Fiber Optics in our trucks. Thanks for the answers!

**jocko** · 04-28-2025, 08:50 PM

see Leon's post #5 in this thread, shows location on the back of the cluster where this ties in.

so question for the electrical gurus.. since the stinger that runs up the column is just to illuminate the shift indicator when the cluster gauges are also illuminated, does it matter at all into which hole this bulb w/stinger is placed?

asking because I just removed my cluster and this was the only item not connected to anything - and the only open hole on the back of the cluster was one of the indicator lights on the fuel gauge (brake, etc) - which is not what Leon showed in his pic in the link above. I'm wondering if it matters at all which bulb hole on the printed circuit is used.

thoughts?

**dmjlambert** · 04-28-2025, 10:02 PM

There's only 4 illumination bulb holes in the instrument cluster. They turn on with parking lights and headlights and are dimmable. So you would want to use one of those 4 holes for the shift indicator fiber optic. Probably one of the middle 2 would be easiest to route the fiber to.

**jocko** · 04-28-2025, 10:22 PM

thanks djmlambert - it was one of your other posts (post #6) in another thread that helped me figure this out once you noted there were only 4 illum holes (the expanded instrument cluster wiring pic) - thank you! I think my truck's PO may have had this wired up wrong.. i might have never noticed had it not been for this thread popping up today, until after I reinstalled the cluster, of course. for those interested, the lower 4 "x" indicators in djmlambert's post #6 in the link I pasted here are the 4 instrument illum holes (i.e. not the turn signal "x" indicators, the remaining x's).

04-28-2025, 12:56 PM	#1
blukangoo Neighborhood Pickle Slinger Join Date: Jan 2007 Location: Cadolzburg, Bavaria, Germany Posts: 2,228	Instrument Cluster Connector I found this connector on a bulb on the back of the instrument cluster, does anybody know what it is for? It is not connected to anything, it's just there. Attached Images __________________ -------------------------------------------------- My C10 Diary Our cars: 1966 Chevrolet Chevelle 396 - TH350 1967 Chevrolet Impala Station Wagon - TH350 1968 Chevrolet C10/CST 327 TH400/375 1969 Corvette Stingray 350 - Muncie Manual Trans 1969 Chevrolet ElCamino 350 - TH400 1970 Cutlass Supreme Convertible - 350 Rocket - TH350 1973 Camaro LT - New Engine Done - TH350 1973 Corvette Convertible 454 - TH400 1974 Chevrolet Camaro Z28 - TH350

04-28-2025, 01:09 PM	#2
too much stuff Roadtrip! Join Date: Feb 2003 Location: Grand Rapids MN Posts: 14,003	Re: Instrument Cluster Connector That sends light up to your gear selector on the column with an auto trans. __________________ 67 gmc custom lwb dakota truck. Sold...And bought back... And sold again... 69 swb 4x4 project (in progress) 70 c-10 lwb texas truck 70 4x4/BB/bkts/posi/tach(retired) 70 swb (wifes) 70 jimmy camper 71 K-5 factory 2wd 71 cheyenne 4x4/tach/posi/ plow rig 71 Cheyenne20 BB, buckets, tach, tilt, 4 speed 72 jimmy CST wyoming rig 72 jimmy Colorado rig 72 lifted texas 4x4 3/4 ton burb 65 fury conv. 383/auto 65 chrysler 300 "L" 413 auto

04-28-2025, 01:10 PM	#3
HO455 Registered User Join Date: Feb 2016 Location: Portland Oregon Posts: 12,411	Re: Instrument Cluster Connector It is one of the dash lamps for the speedo or fuel guage. The line attached to it is a fiber optic cable that illuminates the gear selector on the steering column. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

04-28-2025, 02:00 PM	#4
blukangoo Neighborhood Pickle Slinger Join Date: Jan 2007 Location: Cadolzburg, Bavaria, Germany Posts: 2,228	Re: Instrument Cluster Connector Well I'll be! I didn't think they had Fiber Optics in our trucks. Thanks for the answers! __________________ -------------------------------------------------- My C10 Diary Our cars: 1966 Chevrolet Chevelle 396 - TH350 1967 Chevrolet Impala Station Wagon - TH350 1968 Chevrolet C10/CST 327 TH400/375 1969 Corvette Stingray 350 - Muncie Manual Trans 1969 Chevrolet ElCamino 350 - TH400 1970 Cutlass Supreme Convertible - 350 Rocket - TH350 1973 Camaro LT - New Engine Done - TH350 1973 Corvette Convertible 454 - TH400 1974 Chevrolet Camaro Z28 - TH350

04-28-2025, 10:22 PM	#7
jocko Senior Member Join Date: Oct 2009 Location: NW IN Posts: 18,118	Re: Instrument Cluster Connector thanks djmlambert - it was one of your other posts (post #6) in another thread that helped me figure this out once you noted there were only 4 illum holes (the expanded instrument cluster wiring pic) - thank you! I think my truck's PO may have had this wired up wrong.. i might have never noticed had it not been for this thread popping up today, until after I reinstalled the cluster, of course. for those interested, the lower 4 "x" indicators in djmlambert's post #6 in the link I pasted here are the 4 instrument illum holes (i.e. not the turn signal "x" indicators, the remaining x's).

04-28-2025, 08:50 PM	#5
jocko Senior Member Join Date: Oct 2009 Location: NW IN Posts: 18,118	Re: Instrument Cluster Connector see Leon's post #5 in this thread, shows location on the back of the cluster where this ties in. so question for the electrical gurus.. since the stinger that runs up the column is just to illuminate the shift indicator when the cluster gauges are also illuminated, does it matter at all into which hole this bulb w/stinger is placed? asking because I just removed my cluster and this was the only item not connected to anything - and the only open hole on the back of the cluster was one of the indicator lights on the fuel gauge (brake, etc) - which is not what Leon showed in his pic in the link above. I'm wondering if it matters at all which bulb hole on the printed circuit is used. thoughts?

04-28-2025, 10:02 PM	#6
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 4,051	Re: Instrument Cluster Connector There's only 4 illumination bulb holes in the instrument cluster. They turn on with parking lights and headlights and are dimmable. So you would want to use one of those 4 holes for the shift indicator fiber optic. Probably one of the middle 2 would be easiest to route the fiber to.



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