Turn Signal Quandries - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jaywashburn · 01-07-2024, 11:32 AM

Fellow members, seeking advise about how to resolve a current electrical that has me a bit flustered. Recently became owner of a '75 K10. For the most part things are pretty sorted out on the vehicle (runs, drives). All of the electrical components operate as they should. I went through & cleaned/replaced all ground straps, fuses, & bulbs on truck.
The one thing I noticed was the hazzard switch knob on steering column was broken off so I ordered a new turn signal switch & knob from a local auto parts store.
Everything on the new switch looked identical to old one except the harmonica plug (it wouldn't mesh with original female counterpart). So, I de-pinned new plug & re-pinned to original plug. After that everything went back together fine.
Upon start up I notice that when I go to use the turn signals (left or right) my hazzard lights come on @ all 4 corners (?).
I checked on the LMC site & they show there are 3 different turn signal switches made for the square bodies (73-76, 77-83, & 84-87). My question is could I have the wrong TS for my era truck ? Is that why I have the errant response when I use my turn signals ?
TIA for any input on this matter !

**old Rusty C10** · 01-07-2024, 12:28 PM

yes once the pins didnt fit id have looked for the correct switch

jaywashburn · 01-07-2024, 04:29 PM

Bob, thanks for the response. I kind of figured it was a case of having the wrong turn signal switch. The parts store I noticed sells that TSS & lists it for all square body trucks ('73-87). Will get the right one for my truck from LMC.

Dead Parrot · 01-07-2024, 04:49 PM

I have a hazy memory(was at least 6 years ago) of similar re-pin issues when I replaced the turn signal switch in my 75. Original column. Also a local parts store switch. But everything worked when I was finished.

Any chance you swapped a pin during your re-pin?

Is the current installed column original to the truck or a swap by a PO? A swap might also explain the plug/pin miss match. If a swap, the PO might have replaced the truck's original plug with the one from the donor vehicle.

jaywashburn · 01-07-2024, 07:14 PM

DP, the column is original to my '75 truck (non tilt, auto column shift). I suppose I could have installed a pin in wrong slot but I doubt it. I can tell you that the color of each wire of the new TSS lines up with the wire color of the original female connector.

**kwmech** · 01-08-2024, 12:26 PM

I only know of 2 different switches, tilt and non tilt column. Even then, the orientation of the wires should be the same so it plugs into the same dash harness

jaywashburn · 01-09-2024, 11:12 AM

kwmech, thanks for reply. I haven't had a chance to revisit my electrical gremlin but I am sure that the new TTS is the same as the original with the exception of the harmonica plug.The orientation of wires (connector to connector) is spot on also.
I am beginning to think my problem points more to having a ground issue (likely @ front of truck). Will check that next.

01-07-2024, 11:32 AM	#1
jaywashburn Registered User Join Date: Aug 2012 Location: boulder, CO Posts: 52	Turn Signal Quandries Fellow members, seeking advise about how to resolve a current electrical that has me a bit flustered. Recently became owner of a '75 K10. For the most part things are pretty sorted out on the vehicle (runs, drives). All of the electrical components operate as they should. I went through & cleaned/replaced all ground straps, fuses, & bulbs on truck. The one thing I noticed was the hazzard switch knob on steering column was broken off so I ordered a new turn signal switch & knob from a local auto parts store. Everything on the new switch looked identical to old one except the harmonica plug (it wouldn't mesh with original female counterpart). So, I de-pinned new plug & re-pinned to original plug. After that everything went back together fine. Upon start up I notice that when I go to use the turn signals (left or right) my hazzard lights come on @ all 4 corners (?). I checked on the LMC site & they show there are 3 different turn signal switches made for the square bodies (73-76, 77-83, & 84-87). My question is could I have the wrong TS for my era truck ? Is that why I have the errant response when I use my turn signals ? TIA for any input on this matter !

01-07-2024, 12:28 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,261	Re: Turn Signal Quandries yes once the pins didnt fit id have looked for the correct switch __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

01-07-2024, 04:29 PM	#3
jaywashburn Registered User Join Date: Aug 2012 Location: boulder, CO Posts: 52	Re: Turn Signal Quandries Bob, thanks for the response. I kind of figured it was a case of having the wrong turn signal switch. The parts store I noticed sells that TSS & lists it for all square body trucks ('73-87). Will get the right one for my truck from LMC.

01-07-2024, 04:49 PM	#4
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,478	Re: Turn Signal Quandries I have a hazy memory(was at least 6 years ago) of similar re-pin issues when I replaced the turn signal switch in my 75. Original column. Also a local parts store switch. But everything worked when I was finished. Any chance you swapped a pin during your re-pin? Is the current installed column original to the truck or a swap by a PO? A swap might also explain the plug/pin miss match. If a swap, the PO might have replaced the truck's original plug with the one from the donor vehicle.

01-07-2024, 07:14 PM	#5
jaywashburn Registered User Join Date: Aug 2012 Location: boulder, CO Posts: 52	Re: Turn Signal Quandries DP, the column is original to my '75 truck (non tilt, auto column shift). I suppose I could have installed a pin in wrong slot but I doubt it. I can tell you that the color of each wire of the new TSS lines up with the wire color of the original female connector.

01-08-2024, 12:26 PM	#6
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,391	Re: Turn Signal Quandries I only know of 2 different switches, tilt and non tilt column. Even then, the orientation of the wires should be the same so it plugs into the same dash harness

01-09-2024, 11:12 AM	#7
jaywashburn Registered User Join Date: Aug 2012 Location: boulder, CO Posts: 52	Re: Turn Signal Quandries kwmech, thanks for reply. I haven't had a chance to revisit my electrical gremlin but I am sure that the new TTS is the same as the original with the exception of the harmonica plug.The orientation of wires (connector to connector) is spot on also. I am beginning to think my problem points more to having a ground issue (likely @ front of truck). Will check that next.



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