Electrical gremlin - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cheatham · 02-18-2003, 12:42 PM

Does anyone have any good ideas of how to track down this problem? I keep blowing the instrument/taillamp fuses. I assume it is a short in the wire somewhere, but I haven't found it yet. A couple of other things that may help here. 1) When the instrument cluster does work the left turn arrow is lit up all the time, its been this way for a while. 2) The first time the fuse blew was immediately after having a right rear tire blow out on the highway. ???? 3) The fuse won't blow until I get up to speed, not when the truck is sitting still. 4) Brake lamps dont work when the fuse goes out either.

I am using 20A fast acting fuses in the slot btw.

Hopefully some of this info will ring a bell for some of you guys.

Thanks,
Jack

Locutus · 02-18-2003, 12:49 PM

Have you checked your harnesses. It may be unlikely that a tire could have messed up your wires but it seems like the mostly likely place to start. You definately have a short somewhere.

O'l Buck · 02-18-2003, 03:15 PM

mine used to do that too......now it's doing it again. It's got a couple of bad spots in the wire harness that runs from the firewall to the rear and it bumps the frame and grounds out.

Longhorn Man · 02-19-2003, 12:20 AM

Your lit up turn signal indicator is a bad bulb...either front or back.

krazy_texan · 02-19-2003, 01:26 AM

i just got done with the same problem in the taillights just check your wiring harness (dont forget that it is 30 years old) and always check your grounds that is the most important thing with anything electrical in your truck now with the dash lights it could possibly be a bad dimmer switch but i am not sure as i have not tryed that yet but what many other board members have suggested, hope this all helps

**'68OrangeSunshine** · 02-19-2003, 03:00 AM

I had some wierd gripes in the tail lights of my '67 Suburban. Turned out to be a short in the turn signal harness in the steering column.
Go figure?

cheatham · 02-19-2003, 01:14 PM

Turns out it was a wire shorting out on the frame. Aparently someone did a little bit of "creative" wiring when installing trailer light hookups. There was a hot wire being intermittenly grounded out and I guess some flying tire must have agrivated it.

Also, will the rear side marker light make that blinker light stay on for some reason. I would think only a lamp that actually blinks would cause that and they are all working (I'll double check that though.)

Jack

Hotrod70C10 · 02-19-2003, 09:38 PM

A lit up turnsignal indicator might not be a bad bulb. It could also be a bad ground on one of the turnsignals. I had this problem, I just sanded on the turnsignal mounting points and put it back in. Haven't had a problem yet.

Longhorn Man · 02-20-2003, 12:49 AM

A marker wouldn't cause that...only a front or rear bulb. and Hotrod70C10 is right...a bad ground can also do that.

02-18-2003, 12:42 PM	#1
cheatham I need a brake! Join Date: Jul 2002 Location: Nashville, TN Posts: 474	Electrical gremlin Does anyone have any good ideas of how to track down this problem? I keep blowing the instrument/taillamp fuses. I assume it is a short in the wire somewhere, but I haven't found it yet. A couple of other things that may help here. 1) When the instrument cluster does work the left turn arrow is lit up all the time, its been this way for a while. 2) The first time the fuse blew was immediately after having a right rear tire blow out on the highway. ???? 3) The fuse won't blow until I get up to speed, not when the truck is sitting still. 4) Brake lamps dont work when the fuse goes out either. I am using 20A fast acting fuses in the slot btw. Hopefully some of this info will ring a bell for some of you guys. Thanks, Jack

02-18-2003, 03:15 PM	#3
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	mine used to do that too......now it's doing it again. It's got a couple of bad spots in the wire harness that runs from the firewall to the rear and it bumps the frame and grounds out. __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

02-19-2003, 01:26 AM	#5
krazy_texan Registered User Join Date: Oct 2002 Location: West Des Moines, Ia Posts: 3,233	i just got done with the same problem in the taillights just check your wiring harness (dont forget that it is 30 years old) and always check your grounds that is the most important thing with anything electrical in your truck now with the dash lights it could possibly be a bad dimmer switch but i am not sure as i have not tryed that yet but what many other board members have suggested, hope this all helps __________________ Krazy Texan My Trucks are made with Wrenches not Chop Sticks 1967 GMC 3/4 ton "Johnny Cash" 1990 v1500 suburban 1967 Ford f100 Swb 4x4 "green bean" GOD BLESS JESUS, JOHN WAYNE, AND THE ALAMO

02-19-2003, 09:38 PM	#8
Hotrod70C10 Low & Slow Join Date: Dec 2002 Location: Oklahoma Posts: 1,047	A lit up turnsignal indicator might not be a bad bulb. It could also be a bad ground on one of the turnsignals. I had this problem, I just sanded on the turnsignal mounting points and put it back in. Haven't had a problem yet. __________________ 70' C-10 LWB Fleetside 4.5/6 drop

02-18-2003, 12:49 PM	#2
Locutus Registered User Join Date: Jan 2003 Location: Santa Fe, Texas Posts: 250	Have you checked your harnesses. It may be unlikely that a tire could have messed up your wires but it seems like the mostly likely place to start. You definately have a short somewhere.

02-19-2003, 12:20 AM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Your lit up turn signal indicator is a bad bulb...either front or back.

02-19-2003, 03:00 AM	#6
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,202	I had some wierd gripes in the tail lights of my '67 Suburban. Turned out to be a short in the turn signal harness in the steering column. Go figure?

02-19-2003, 01:14 PM	#7
cheatham I need a brake! Join Date: Jul 2002 Location: Nashville, TN Posts: 474	Turns out it was a wire shorting out on the frame. Aparently someone did a little bit of "creative" wiring when installing trailer light hookups. There was a hot wire being intermittenly grounded out and I guess some flying tire must have agrivated it. Also, will the rear side marker light make that blinker light stay on for some reason. I would think only a lamp that actually blinks would cause that and they are all working (I'll double check that though.) Jack

02-20-2003, 12:49 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	A marker wouldn't cause that...only a front or rear bulb. and Hotrod70C10 is right...a bad ground can also do that.



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