No turn signals, where to look? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1973GMC_1500 · 03-26-2010, 07:50 PM

I lost turn signals on my '87 K20 (just got it up and running w/ different engine last week). The fuse is good, I swapped the relay with a known good one, and I have power at the fuse block.

Any thoughts? I don't know of any underhood wires I could've messed up when I swapped the engine that would affect the turn signals.
I really don't want to tear into the steering column to replace the switch, been there, done that, it SUCKS.

flamingbig10 · 03-26-2010, 08:13 PM

check the junction box on the firewall, or the bulbs are bad

fixit-p · 03-26-2010, 08:17 PM

Do your hazard lights work?

James McClure · 03-27-2010, 09:31 AM

A quick question, did they work before the swap? Next, like mentioned above, do the 4 way's and brake lights work? Next, apply the 4 way's and step on the brake. Everything (all signal lights outside and dash indicators should light up) Release the 4 way's and keep the brake lights on. Signal left and see if the left rear light goes out, do same for right. All the above will check all the wireing for the signal light circuts EXCEPT B+ to the signal light switch and thats simple to check with a test light at the switch harnace connector. If you have all this, chances are pretty good the switch is bad. If you find a power loss check the fuse links. Hope this helps, Jim

1973GMC_1500 · 03-28-2010, 10:07 PM

I will check it out. The lights did work before the swap, but I don't remember exactly when they quit.
I don't think my brake lights work, I don't know if they ever did (never really noticed)

I'll run through a few of those tests tomorrow night if I have time.

03-26-2010, 07:50 PM	#1
1973GMC_1500 Registered User Join Date: Jan 2010 Location: Oran, IA Posts: 78	No turn signals, where to look? I lost turn signals on my '87 K20 (just got it up and running w/ different engine last week). The fuse is good, I swapped the relay with a known good one, and I have power at the fuse block. Any thoughts? I don't know of any underhood wires I could've messed up when I swapped the engine that would affect the turn signals. I really don't want to tear into the steering column to replace the switch, been there, done that, it SUCKS. __________________ '87 GMC K2500 Factory 6.2 Diesel, 4 speed. Converted to 350 (has cracked block) converting back to 6.2 '82 [COLOR="Sienna"]Cadillac Coupe Deville 350 DIESEL '93 Chev S10 2.8L 5 speed '98 GMC K1500 Z71 ext cab shortbox 6.5 DIESEL '96 Ford F250 7.3 Powerstroke

03-26-2010, 08:13 PM	#2
flamingbig10 6.0 powered square Join Date: Feb 2008 Location: Mesquite texas Posts: 3,459	Re: No turn signals, where to look? check the junction box on the firewall, or the bulbs are bad __________________ Aaron 1980 c-10 short bed lowered, cammed 6.0, 4l80e 3600 stall, smp tune, wilwoods, and flames best time so far best et 7.86 @87 on motor 7.57 90 on a 75 shot Build http://67-72chevytrucks.com/vboard/s...d.php?t=283326

03-27-2010, 09:31 AM	#4
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: No turn signals, where to look? A quick question, did they work before the swap? Next, like mentioned above, do the 4 way's and brake lights work? Next, apply the 4 way's and step on the brake. Everything (all signal lights outside and dash indicators should light up) Release the 4 way's and keep the brake lights on. Signal left and see if the left rear light goes out, do same for right. All the above will check all the wireing for the signal light circuts EXCEPT B+ to the signal light switch and thats simple to check with a test light at the switch harnace connector. If you have all this, chances are pretty good the switch is bad. If you find a power loss check the fuse links. Hope this helps, Jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

03-28-2010, 10:07 PM	#5
1973GMC_1500 Registered User Join Date: Jan 2010 Location: Oran, IA Posts: 78	Re: No turn signals, where to look? I will check it out. The lights did work before the swap, but I don't remember exactly when they quit. I don't think my brake lights work, I don't know if they ever did (never really noticed) I'll run through a few of those tests tomorrow night if I have time. __________________ '87 GMC K2500 Factory 6.2 Diesel, 4 speed. Converted to 350 (has cracked block) converting back to 6.2 '82 [COLOR="Sienna"]Cadillac Coupe Deville 350 DIESEL '93 Chev S10 2.8L 5 speed '98 GMC K1500 Z71 ext cab shortbox 6.5 DIESEL '96 Ford F250 7.3 Powerstroke



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.